Only a small portion of the Federal Government's recent $39 billion promise for shipbuilding will actually come to South Australia, a leading defence industry body says.

Key points: Federal Government announced $39 billion Navy ship-build for Adelaide earlier this month

Federal Government announced $39 billion Navy ship-build for Adelaide earlier this month Defence Teaming Australia says only $8 billion will be spent in SA

Defence Teaming Australia says only $8 billion will be spent in SA Decision on who will win submarine build contract not expected until next year

Prime Minister Tony Abbott announced a new fleet of Navy ships would be built in Adelaide to replace the current ANZAC Class frigates, during a recent visit to the city.

Mr Abbott said 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".

On Thursday in Question Time, Mr Abbott repeated the $40 billion figure claiming Defence Teaming Australia had fed the media "false and misleading information".

"I want to make it absolutely crystal clear, when this Government said that we would spend some $89 billion on fleet building we were talking about acquisition, not sustainment ... almost $40 billion will be spent on a fleet build centred in Adelaide on acquisition," he said.

But Defence Teaming Australia predicted only about $8 billion out of the pledged $39 billion build would go towards the local build, after it conducted its own budget breakdown.

Chief executive Chris Burns said the rest of the money would go towards maintenance and sustainment works, which tend to be done interstate.

"Those ships will be home ported in Western Australia and New South Wales," Mr Burns said.

"I think they could have been more transparent to explain how the figure breaks down."

Mr Burns said the $8 billion would still help to boost job numbers.

But he said the focus must now shift to securing submarine building in South Australia.