Former prime minister Tony Abbott warns Australia might need a plan B for its acquisition of a new fleet of submarines.
Mr Abbott is scheduled to deliver a "leadership lunch" speech to the Centre for Independent Studies in Sydney on Thursday entitled: "Submarines: why settle for second best?".
It's believed Mr Abbott will use the speech to call for Australia to embrace nuclear-powered submarines.
"I think it's important that we have a plan B, given the submarine acquisition process as outlined is a long and involved one," he told 2GB Radio on Wednesday.
Last November, during a charity dinner in Port Moresby Mr Abbott, said one of his greatest regrets as prime minister was not giving more consideration to off-the-shelf nuclear-propelled submarines.
His government set up the three-way race between Japan, Germany and France for the submarine contract.
French shipbuilder DCNS won the design job and the 12 conventional-powered submarines will be constructed in Adelaide.
The first steel is expected to be cut by 2022, and the first sub will enter service in the early 2030s.