Firefighters are continuing to battle an out-of-control bushfire west of Port Lincoln on South Australia's Eyre Peninsula throughout the night.

More than 500 hectares of scrub have been burnt in the blaze, with the fire just six kilometres from the city.

Large plumes of smoke and ash could be seen across the region, and many nearby residents evacuated their homes as a precaution.

As yet there have been no reports of injuries or property damage.

The blaze broke out at Mungerowie Scrub, west of Port Lincoln, late on Tuesday morning.

About 180 firefighters are on the scene trying to bring the fire under control.

Conditions have cooled during the night but the Country Fire Service (CFS) says residents must remain vigilant.

Temperatures had peaked above 36 degrees on Tuesday before the cool change.

CFS spokesman Malim Watts says although the intensity of the fire has been reduced, homes could still be at risk.

"I can't emphasise enough the fact that people need to be vigilant," he said.

"They need to have a bushfire survival plan and make sure they have a situational awareness and are able to access information as soon as they need to."

ABC Local Radio on 639 AM in the Port Pirie region and 1485 AM in the Port Lincoln region is broadcasting updates.

Look back on the developments as they happened throughout the day. All updates ACST.

9:32pm: The Country Fire Service says the intensity of the bushfire near Port Lincoln has reduced.

Spokesman Malim Watts says properties could still be at risk and residents should not be complacent with this evening's cooler conditions.

"The intensity of the fire has reduced," he said. "At this stage the fire is not declared contained or safe, so people still need to be vigilant and still need to have a bushfire survival plan [because] the situation could change."

7:48pm: Fire crews continue to battle a blaze which is burning in scrub about six kilometres west of Port Lincoln.

About 180 firefighters are working to contain the fire, which has burnt an area of more than 500 hectares.

The CFS says the fire front is moving in an easterly to north-easterly direction.

5:35pm: Adam Pearce lives at Port Lincoln South and has decided to evacuate with his family.

He says it is the third time he has had to leave the area because of fire.

"We can see the haze over the bay and we can just see like kind of a dark-brownish colour smoke in the clouds and my Mum went up the hill further up the street where we're staying, and we were getting ash on top of us."

5:05pm: Residents near the bushfire who are trying evacuate say people taking photos are causing problems for those people trying to leave.

Morgan Pilgrim is an evacuee and says she almost crashed several times as she left her home.

"On our way out obviously the sticky-beakers were a bit of a problem. "Trying to leave we nearly had a few accidents as people were just stopping in the middle of the road and taking photos and what have you. "I think the message to those people perhaps is hop out the way because it is important for people to get out of their houses in a situation like this."

4:30pm: Thick smoke and ash continue to blow across Port Lincoln as the north-west of the town remains under threat from an advancing bushfire.

Dozens of fire crews are on the job, including from the air, hoping to make progress before nightfall.

ABC Local Radio continues to broadcast all the latest details on the fire emergency.

Smoke billows from a bushfire west of Port Lincoln ( Audience submitted: Hamish Robertson )

4:10pm: There are about 120 firefighters and five water-bomber aircraft currently in action against the bushfire near Port Lincoln.

The blaze is about seven kilometres north-west of Port Lincoln

There is ash and thick smoke blowing across the town.

Country Fire Service deputy chief officer Andrew Lawson says no homes we being directly threatened at this stage but the fire front is edging closer to properties.

"We are most concerned about a strong south-west wind change coming through the area this afternoon and this evening," he said. "In fact the wind change is starting to impact on the fire ground at the moment so that has the potential to push this fire in an easterly direction towards Port Lincoln."

The temperature in Port Lincoln has dropped to the mid-20s, down about 10 degrees Celsius on the day's maximum.

In Adelaide, thunderstorms are rolling in from the west.

The maximum temperature peaked above 36 degrees before the change.

4:00pm: Resident Ian Adams is near Winter Hill lookout, about five kilometres from Port Lincoln, and says all he can see is smoke.

"Well, everyone else has left and taken some gear with them and I'm just waiting to turn on my sprinkler system if I need to. "If needed I'll switch them on and I'll be out of here."

3:40pm: As the Eyre Peninsula blaze continues in the west, a lightning band has now reached the lower south-east of South Australia.

Strikes have sparked grass fires and CFS crews and water bombers are responding to outbreaks at Southend, Bray and Clay Wells.

Simon Timkey from the weather bureau says an extreme fire danger warning is in force for the south-east SA region.

"We've got pretty fresh to strong northerlies so it is a bad fire weather day and with the dry air down low [humidity]," he said. "If a lightning strike was to start a fire then that fire would be pretty difficult to contain I would think."

Lightning may also have started other fires reported in the Adelaide hills and to the south of Adelaide.

Map of the fire area at 1500 ACDT

3:00pm: A wind change has reduced the extreme temperatures on lower Eyre Peninsula as the bushfire continues to burn toward Port Lincoln, fanned by a westerly wind.

The State Emergency Service says tents are being sent to Port Lincoln for an evacuation centre, which will be in place by midnight.

The CFS says the fire is threatening the north-west of Port Lincoln, and it is not aware of any houses lost.

The focus of fire-fighting efforts is the eastern front of the blaze.

As for how the bushfire started, the CFS says there was lightning in the area on Monday night but could not provide any definite information.

Primary Industries SA has set up a refuge for animals, including horses, at Tumby Bay. Animal health inspector Emily Litzow can give details on 0408 539 060.

The CFS has attended close to 50 fires across South Australia so far today, in high temperatures and with strong winds buffeting the state.

A cooler change is moving slowly across the state from the west and is not expected in eastern areas of SA until evening.

Sorry, this video has expired Crews working feverishly to stop SA bushfire

View across Port Lincoln as the bushfire nears ( Melissa McNab via ABC Eyre Peninsula )

Dark smoke over Port Lincoln, viewed from the hospital ( Kim Smith via ABC Eyre Peninsula )

Plume of smoke rises west of Port Lincoln ( Chris Morrison via ABC Eyre Peninsula )

2:20pm: Port Lincoln library has been evacuated as a bushfire approaches the town from the west.

Water-bombers and fire crews on the ground are tackling the blaze, which has burnt through more than 500 hectares.

Further east in South Australia, the weather bureau fears a lightning band heading for the lower south-east region could cause bushfires.

The area has had temperatures in the low 30s and strong northerly winds so far today.

Simon Timkey from the bureau says the thunderstorms should hit the south-east SA region by about 4:00pm.

"Looking at the line at the moment it is reasonably active but it is heading east to south-east, so a good bit of it will stay offshore," he said. "But it only takes one lightning strike to start a fire."

2:00pm: The Eyre Peninsula bushfire is about 10 kilometres west of Port Lincoln.

A safety precinct has been established at Port Lincoln at the Kirton Point Bowling Club.

Country Fire Service co-ordinator Leigh Miller says the fire is continuing to expand.

"It looks to be about a kilometre wide and about five kilometres long as an estimation at the moment," he said. "It is getting bigger under the influence of a north-westerly wind. We're seeing the fire flanks becoming extended and once the wind changes (more westerly) that will mean there's a wide fire front heading towards Port Lincoln."

Smoke billows from the bushfire ( Audience submitted: Kirsty Lobb )

Smoke west of Port Lincoln ( via ABC Eyre Peninsula )

1:25pm: SA Power Networks is warning electricity infrastructure is likely to be damaged by the Eyre Peninsula bushfire.

Official Paul Roberts says it is unlikely there will be any decision made to cut the power supply to Port Lincoln.

He says any power outages in the region are likely to be the result of damage to the electricity supply network.

"We wouldn't turn off the power to Port Lincoln but there is certainly a threat by this fire from where it's heading," he said. "There is a threat to supply into the surrounding area where the fire is burning and areas further on which maybe supplied by lines which run through the fire area."

Aden Kraft took a photo of the fire approaching his property ( Aden Kraft via ABC Eyre Peninsula )

1:15pm: Andrew Lawson of the Country Fire Service says the bushfire west of Port Lincoln had burnt about 500 hectares and the winds from the north-west are gusting at 40-60kph.

The eastern flank of the fire is about four kilometres wide.

The CFS says the blaze could reach Port Lincoln later in the afternoon if the winds swung further west.

Mr Lawson says that could be in 2-3 hours depending on the wind strength and success of fire crews in that time.

Sorry, this video has expired SA fire crews battling windy conditions ( Joe O'Brien )

1:00pm: There are reports of flames up to 15 metres high from the Eyre Peninsula bushfire.

Kiwi White is a resident of the area and says he is leaving his home because he can see the fire in the distance.

"It's not that far away, I've got binoculars but you can see the flames when they flare up. They probably go up 10-15 metres in the air," he said. "You see it all red and then the black smoke will just engulf it and then there's a huge plume of white smoke at the head and black smoke it goes up like a nuclear bomb and it's going very high into the sky."

12:50pm: There are strong northerly winds and the Country Fire Service says a wind change in the next half hour or so is likely to send the fire toward Port Lincoln.

Locals are complaining sightseers are in the area wanting to see the blaze and take photos, and are hampering fire-fighting crews.

Water bombers and ground crews on the scene ( ABC: Emma Pedler )

11:50am: The Country Fire Service (CFS) says homes and properties are being threatened as the fire burns in a region where a catastrophic fire danger rating is in force due to extreme weather.

It says the fire is burning out of control at Mungerowie Scrub, west of Port Lincoln, near Big Swamp.

A change of wind direction in the early afternoon could push the flames toward Port Lincoln, near Western Approach Road and Duckpond Drive, the CFS warns.

The CFS says people in that area may be at risk.

A week ago, a bushfire on the lower Eyre Peninsula destroyed property in the Sleaford Bay area and burnt close to the town of Tulka, south-west of Port Lincoln.

Fire crews were called to the area earlier today because of a flare-up from that blaze.

The CFS now says the fire was sparked by lightning.