Volunteer fire crews say emergency communications systems failed them as a massive bushfire burnt north of Adelaide last week, and the South Australian Government has promised an independent review of what went wrong.

Key points: Independent review will look at communications failings

Independent review will look at communications failings Crews rely on Government Radio Network and Telstra mobile network

Crews rely on Government Radio Network and Telstra mobile network CFS officer says black spots across SA need to be addressed

Country Fire Service (CFS) Gilbert Valley group officer Andrew Allchurch told 891 ABC Adelaide "the radio network, when we needed it most, was not there".

"We had no communications at the height of the fire," he said.

"When we wanted to put messages out to the regions to put warning messages out to the public, the radio network wasn't there to be used.

"It was either busy, or we had no reception."

As well as the Government Radio Network (GRN), a system used by fire brigades, police, ambulance crews and authorities such as SA Water, crews rely on Telstra's mobile phone network for coverage, but Mr Allchurch said it was also "very problematic" at the height of the emergency last Wednesday.

"Most of my communications back to the CFS regional staff in the headquarters was done on the mobile network — when I could get communications with the phone towers," the Gilbert Valley firefighter said.

"In the northern part of the fire the communications were terrible."

He said some crews could do no more than take shelter as the fire front passed, as they were left with no way to communicate with base.

"I know of three brigades that reported to me that they tried to press the emergency button — there's an emergency button on the GRN radios that's meant to take the right of way over all communications through the Government Radio Network but, you know, they were left to fend by themselves and all I can say is thank God there's not more deaths because of this," he said.

The threat from the Pinery bushfire was officially reduced by the CFS on Tuesday evening, six days after the fire began.

Independent review of bushfire promised

Emergency Services Minister Tony Piccolo said there would be a review to identify what could be done to improve communications and safety during an emergency.

Tony Piccolo says a bushfire review will be done independently of his office and Government. ( ABC News )

"The review which we'll be announcing shortly will look at what we need to do — that will be independent, it won't be anybody in my office or Government, it will be an independent review," he said.

"I don't know what caused the failure in this situation, whether some towers went down. We need to see if there was something broader at work."

Mr Allchurch said he last met Mr Piccolo about four weeks ago to discuss communications "black spots" in his brigade's region, north of Adelaide.

"We've brought this [issue] to the Government's attention, the CFS's attention for the last 13 years, but nobody's taken any notice of us because they keep coming back to us and saying it meets the Government's [performance] agreement with Telstra," he said.

"If there were more towers out there they would help with [avoiding] the congestion, as we really relied the other day on two or three towers.

"In the Sampson Flat fire [last January in the Adelaide Hills] I think they were coming off 12 towers so it gives you some idea."

Mr Allchurch said the emergency communications network was failing fire crews.

"Most of these are volunteers, they put their lives on the line to fight these fires but they're just getting a second-grade system," he said.

"It might suit some other [emergency] services, but when the CFS needs it the most it's not there.

"That fire burnt very quickly, roughly 35,000 acres an hour, it roughly burnt 580 acres a minute so to comprehend that [it shows] that fire travelled in extreme conditions."

Fire affected some mobile towers

Mr Piccolo said some mobile phone towers were affected by the bushfire itself.

Several CFS fire units were out of communications contact during the emergency (file photo). ( ABC News: Angelique Donnellan )

"We need to understand what went wrong because in this fire three of the Telstra towers actually all burnt out and had to be actually restarted, so I need to understand fully what we'll need to do to future-proof our systems," he said.

"Digital upgrades [of the GRN] will improve coverage, certainly will improve capacity and reliability. Will it address every issue? Not necessarily.

"I'm not going to suggest it has no flaws and that's why we're actually upgrading it for the digital network and that's why we need to also look at complementary systems. No network will actually be 100 per cent — we need to put measures in place to make sure if one network doesn't reach everybody, the others do."

Mr Allchurch said he warned Mr Piccolo when they met recently at his Gawler electorate office that he would have "blood on his hands" if emergency communications black spots were not addressed.

Mr Piccolo said he did not recall the CFS officer using such language, but he had taken on board the matters raised at that meeting and earlier ones.

Mr Allchurch said the issue was a statewide one, not just for the Gilbert Valley.

"It's not only our area, there's black spots and danger spots all across the state — Yorke Peninsula, further north, down the south-east, on the west coast, it's not just only our area," he said.