Four million litres of water are being pumped every day into a peat fire in south-west Victoria that has been smouldering at Lake Cobrico since St Patrick's Day.

That is the equivalent of four Olympic swimming pools' worth of water each day, or 50 litres per second.

To achieve this task, firefighters have teamed up with Wannon Water to construct a 4 kilometre-long pipeline, which taps into the principal water main in the district west of Camperdown.

The segmented pipe pumps water 24 hours a day alongside roadsides and across paddocks until it reaches two dams dug at the edge of the peat fire at Lake Cobrico.

The 4km-long pipeline pumps 4 million litres of water per day. ( ABC South West Victoria: Matt Neal )

State emergency management commissioner Craig Lapsley said that with no decent rainfall on the horizon, an above-ground temporary pipeline was deemed the only feasible way to get a constant and significant amount of water onto the peat fires.

"One of the challenges with peat fires is we need water," Mr Lapsley said.

"The fact that we've got a forecast … of potentially no rain or very limited rain for the month of April means that we've looked at every other source available.

"One of those is to put above-ground piping to bring [water] from a major reticulation main — it's quite extensive but necessary without rain."

The construction of the pipeline took just 48 hours — one expert said such a feat would ordinarily take weeks — and is understood to be the first time such a method has been used to fight a peat fire in Victoria.

Water is sprayed on the peat fire, while an excavator digs a trench around the area. ( ABC South West Victoria: Matt Neal )

Race against time as residents flee

If it is left to burn, the peat fire could spread through the vegetable matter up to 10m below the surface and damage prime farming land.

The Cobrico peat fire as it appeared on March 24. ( ABC South West Victoria: Matt Neal )

It could also burn for months — a peat fire in Indonesia in 1997 lasted almost six months and was only extinguished by monsoonal rains.

Additionally, the carbon monoxide seeping from the blaze is incredibly toxic and has already caused about 20 per cent of local residents to evacuate the area.

Farmers and residents still working and living in the area have been encouraged to undergo regular health checks.

At least one person was taken to hospital last month suffering the effects of carbon monoxide poisoning.

Wannon Water's Glenn Jeffrey at the start of the 4km pipeline near Boorcan. ( ABC South West Victoria: Matt Neal )

Pipeline part of multi-pronged approach

Wannon Water's Glenn Jeffrey said the pipeline was just one part of a major assault on the fire.

"The temporary pipeline is running into a dam system, and then there are irrigation pumps from there going into sprinklers," Mr Jeffrey said.

"[The water is] also being used to flood a trench around the fire which will act like a fire break underground.

"The water used in the sprinklers is directly attacking the fire, whereas the channel is in place to stop the peat from burning any further — it will hit that water and stop," he said.

Water bombers are also doing their bit, targeting hot spots with water from the nearby Lake Cobrico.

"The burnt area is quite inaccessible," Mr Jeffrey said.

"The peat itself is hot and it's soft.

"They can't get fire tankers in there so that's where the aircraft come into it."

Water bombers are part of the plans to extinguish the Lake Cobrico peat fire. ( ABC South West Victoria: Matt Neal )

The principal water main the temporary pipeline taps into is the North Otway Pipeline Supply, which runs from the Otways to Warrnambool, supplying water to towns along the way.

"There were a lot of questions around [whether] we'd have enough water to supply the other towns that share this pipeline [but] we're pretty confident it won't impact any towns," Mr Jeffrey said.

"The results of the maths were pretty comprehensive that we could run this pipe for a long time without impacting on the pressures and flows in the downstream towns."