Up to 2,500 shipbuilding jobs in Adelaide will be safe for "all time", the Prime Minister says, ahead of the expected announcement to build a new fleet of Navy ships worth $39 billion.

The Prime Minister's Cabinet is in Adelaide for a three-day visit where local polling has suggested the Federal Liberal Party is out of favour as the state suffers with the highest unemployment rate in the country.

Mr Abbott told 891 ABC Adelaide this morning that a frigate build would be brought forward to start in 2020, and result in 2,500 SA surface shipbuilding jobs.

Contracts to build offshore combatant vessels (OCV) or "corvettes" would be brought forward to 2018.

He said a competitive evaluation process for both projects would begin in October, on the proviso that any bidders pledge to conduct the "major build in South Australia".

The Future Frigates were flagged in the 2009 defence white paper (DWP) as a replacement to the ANZAC Class frigates.

The Government said in the DWP it would acquire eight frigates to gradually replace the ANZAC Class ships, which themselves would continue to be maintained and upgraded until their replacement.

An announcement to build the frigates would come after months of intense debate about defence shipbuilding contracts, including a $50 billion fleet of 12 new submarines the Government promised to build in SA prior to the election but subsequently threatened to send offshore once in power.

Navy surface ships replaced Australia has eight Anzac Class frigates, which are smaller than Air Warfare Destroyers but larger than patrol boats

Australia has eight Anzac Class frigates, which are smaller than Air Warfare Destroyers but larger than patrol boats They are to be replaced with a new fleet designed with an emphasis on submarine detection and response

They are to be replaced with a new fleet designed with an emphasis on submarine detection and response The future frigates will be designed to support both combat helicopters and unmanned aerial vehicles, or drones

The future frigates will be designed to support both combat helicopters and unmanned aerial vehicles, or drones The ANZAC Class ships will continue to be maintained and upgraded until they are no longer required

The ANZAC Class ships will continue to be maintained and upgraded until they are no longer required The 2009 defence white paper (DWP) planned for up to 20 new Offshore Combatant Vessels (OCV), or patrol boats

The 2009 defence white paper (DWP) planned for up to 20 new Offshore Combatant Vessels (OCV), or patrol boats They will replace the Navy's fleet of four different types of modular patrol boats into a single multi-role class

They will replace the Navy's fleet of four different types of modular patrol boats into a single multi-role class They are expected to be be larger than the current Armidale Class patrol boats and weigh up to 2,000 tonnes

They are expected to be be larger than the current Armidale Class patrol boats and weigh up to 2,000 tonnes The DWP said the OCVs will be used for "warfighting roles", border protection, and long range counter-terrorism and counter-piracy operations

The Government has also put local control of the Air Warfare Destroyer (AWD) project out to tender after being unimpressed with cost blowouts and the length of time it took for ASC in Adelaide to float the first of three ships it has on order.

It is now believed the Government's announcement on an earlier surface ship build is being made to deflect ongoing criticism about the far more lucrative submarine project.

Defence Teaming Centre chief executive Chris Burns said it would detract from ongoing concerns about the future of submarine building in SA.

"Well we hope the announcement isn't just a one-ship project in isolation," he said.

"What we need in Australia is a national shipbuilding plan that encompasses Navy and non-Navy requirements and to demonstrate that we can build not only good major surface warships, we can build submarines and other ships as well."

The Government's backtracking on its pre-election promise to build the submarines in Adelaide has contributed to a decline in the polls for its SA federal members, including Education Minister Christopher Pyne.

The contract has been put out to international tender in what the Government calls a "competitive evaluation process", with Japan, Germany and France bidding for the contract.

"The frigates are coming as a first prize," Mr Abbott said.

"One way or another, the subs will be coming as a further prize. Whatever the the competitive evaluation process turns up, there will certainly be more submarine jobs in SA."

Mr Abbott said SA would not be able to avoid the so called "valley of death", when shipbuilding contracts finish up because of a gap in projects.

He said jobs would drop from about 2,000 to 1,000 but would then build up to about 2,500 from 2020 onwards.

"It's a terrific announcement for Adelaide, up to 2,500 shipbuilding jobs, safe for Adelaide, for all time," Mr Abbott said.

Premier Jay Weatherill said SA has been overlooked by the Federal Government for too long.

"We've been putting a lot of effort into explaining to the Commonwealth the size of the challenge the urgency of the challenge and the fact that up to this point we haven't been receiving the attention of the national government," he said.

"I think that message is getting through to the Prime Minister."

A commitment to naval shipbuilding in SA could not come at a better time for the state, with the Australian Bureau of Statistics showing the state with an unemployment rate of 8.2 per cent in June - its worst jobless rate in 15 years and the highest in the country.

PM trying to save job: Bill Shorten

Federal Opposition Leader Bill Shorten has accused the Prime Minister of using the Adelaide naval shipbuilding contract to "save his own job".

"I think as all Australians know, Mr Abbott views these multi-billion-dollar, multi-thousand-job contracts as political prizes aimed at just saving his own job," Mr Shorten said.

"This naval shipbuilding contract, this money should go - these resources should go to Australian shipyards, not just in Adelaide but throughout the nation, they should be based upon prioritising Australian jobs in the national security of Australia."

Labor Senator Stephen Conroy, who spoke in Melbourne this morning, said 600 jobs were "on the block" in Williamstown, Victoria as the Federal Government created "a circus in South Australia to protect Tony Abbott's job and Christopher Pyne's job".

"They have broken their promise [made] before the last election to build submarines in South Australia and now what we're seeing is Tony Abbott scrambling to try and make up ground because of the crisis he's created across this country's ship building industry," he said.

"We're seeing jobs already being lost in Newcastle, we've already seen jobs lost here in Williamstown and there are 600 more jobs on the chopping block because Tony Abbott has spent two years doing nothing about this crisis he's created."