Australian defence officials have been urged to consider round-the-clock dehumidification systems at an Air Force base near Newcastle to curb the corrosion risk for its fleet of Joint Strike Fighter jets.

Key points: A KPMG report shows corrosion risks from salt to 72 F-35 Joint Strike Fighters at the Williamtown RAAF base

A KPMG report shows corrosion risks from salt to 72 F-35 Joint Strike Fighters at the Williamtown RAAF base The report warns aluminium parts are susceptible, and recommends full-time dehumidification

The report warns aluminium parts are susceptible, and recommends full-time dehumidification The fighters are the largest acquisition in the Air Force's history, costing $17 billion

Auditing and consulting firm KPMG was tasked with doing a report on the "intergranular corrosion mitigation options" for the 72 F-35A fighter jets, bought by the Australian Defence Force for $17 billion.

Concerns over the risk of metal stress and cracking were raised in 2017, the year before the next-generation fighters were due to come to Australia.

The FOI report obtained by the ABC said of the three bases where the jets would be based, only Williamtown, near Newcastle, had been identified as having potential problems.

The risk is posed by salt and other climatic conditions.

What's intergranular corrosion?

The first F-35A Joint Strike Fighters were delivered to Williamtown RAAF base in December last year. ( ABC Newcastle: Ben Millington )

Intergranular corrosion occurs as a chemical reaction between metal and the environment.

"It can degrade the material properties causing stress cracking and cause tensile stress which can impact adjacent components", the report said.

The report points to Aluminium Alloy 7085, used in the construction of the F-35 — the first time the material had been used in widespread production of a military aircraft.

"AA 7085 is reported to have increased susceptibility to intergranular corrosion," the report said.

The jets will also be based at Luke Airforce Base in the US state of Arizona, and the RAAF base at Tindall in the Northern Territory.

"While up to 54 of the fleet of 72 aircraft can be housed at Williamtown at any one time, all aircraft will be rotated through Williamtown and are therefore susceptible to intergranular corrosion," the report said.

As a result, KPMG recommended the full-time use of mobile dehumidification units, in conjunction with other systems.

The projected costs for the infrastructure have been redacted in the KPMG report released through FOI.

When the first of the next-generation fighter jets arrived at Williamtown RAAF base in December 2018, the Defence Minister Christopher Pyne said each plane cost $124 million and represented good value for money.

"This is the largest acquisition of the Air Force's history, $17 billion, and arguably the most lethal in the Air Force's history, certainly of its time," Mr Pyne said.

But the Joint Strike Fighter has been plagued by delays and cost overruns in the United States and concerns ranging from overheating to unreliable software platforms.