Defence Minister Linda Reynolds has left the door open to shifting maintenance for Australia's Collins class submarines to WA after the state's defence issues minister Paul Papalia went public with a pitch for the work.

But a decision to relocate "full cycle docking" to the west would create political angst in South Australia, where the complete maintenance program is now located, and cross-bench senators have issued a veiled threat to Prime Minister Scott Morrison threatening to thwart his legislative agenda if he fails to issue an assurance the work would stay put.

Speaking in Perth on Monday, Defence Minister Linda Reynolds said the government had yet to decide on whether submarine maintenance would be moved to WA from South Australia. Credit:AP Photo/Rick Rycroft

In Perth on Monday, Senator Reynolds said no decision on a move been made, but said she had been working with the governments of both states and Australia's $90 billion shipbuilding plan would create industrial opportunities and jobs on both sides of the border.

"I have been a very passionate advocate for our state but now as the minister for defence I've also got to make sure that any decision we take is in our nation's interest," she said.