Defence officials have been pushed to assure Australians they would not receive "rust buckets" from the US after previous ships were taken out of service with problems.
Tasmanian senator Jacqui Lambie raised concerns about rust, failing parts and maintenance problems on the US submarines, with Australia poised to buy at least three of the boats.
Senator Lambie referred to the state of two US-built ships forced to be taken out of action saddled with rust.
"Is it fair to say that the (HMAS) Manoora and (HMAS) Kanimbla were rust buckets?" she asked defence officials at a Senate hearing on Wednesday.
"We cannot go back to that or we're not learning anything.
"We do not want to be picking up the pieces here."
Senator Lambie also produced photos of rusted American submarines.
Navy chief Vice Admiral Mark Hammond said the photos were of submarines that had been on deployment for six and seven months and each travelled more than 38,000 nautical miles.
The vice admiral said it was normal for submarines to head into port for maintenance after operating in tough environments and at differing speeds.
He said the surface rust was a maintenance issue that was cleaned off at the next docking and it doesn't lead to corrosion of the thick steel.
"This is indicative of a hard-working submarine coming back off patrol," he said.
"The result is wear and tear of extended operations throughout the Indo-Pacific or Atlantic."
He said the US navy was a "highly capable" and lethal force and any submarines delivered to Australia would have a life span of at least 20 years.
"The discussions I've had with the US navy is that they will be focused on giving us robust, reliable nuclear-powered submarine capability," he said.
Chief of the nuclear-powered submarine task force Vice Admiral Jonathan Mead added that Australia was "working with (the US) to transfer their best submarines to Australia".
The first US-built nuclear submarine is slated to arrive in the early 2030s before a jointly built AUKUS class submarine enters into service about a decade later.
The navy chief said America is also working to ensure Australia has the technical capability and educated crew to man the complex vessels as the defence force struggles with retention issues.
Defence officials were also grilled about personnel leakages and the need to put a retention bonus in place as it tries to expand the force by thousands of boots.
Major General Wade Stothart said Australia had not been immune to broader economic factors impacting staff retention.
The defence force was flipping its model and going to the public for recruitment rather than waiting for people to come to them, he said.
Research showed young people were less interested in joining the force as they have a range of other employment options.
"So the marketplace has become more competitive for us," he said.
The defence department will fast-track processes and boost recruitment efforts in rural and regional areas to tackle personnel shortfalls after missing its targets.
The centrepiece of the new recruitment drive is having people signed up and ready to go within 100 days of applying in order to stop them being poached by other employers.
