Federal Labor is adopting a cautious approach to a strategic plan that aims to increase by 5000 the number of uniformed personnel in the defence force.
The next defence white paper - the third in seven years and due for official release on Thursday - will commit the government to honouring an election promise to increase defence spending to two per cent of gross domestic product within 10 years.
Prime Minister Malcolm Turnbull said the paper, which he described as a "very substantial piece of work", would focus on securing the nation.
It would be fully costed, unlike Labor's previous efforts, he told reporters in Canberra on Wednesday.
The 5000 new uniformed personnel will be spread across all three armed services and take Australian Defence Force numbers to 63,000.
The paper will outline major acquisitions including new warships, including nine new frigates and a number of offshore patrol vessels.
It's likely the white paper will nominate the acquisition of at 12 new submarines, matching the number Labor governments promised in their strategic plans in 2009 and 2013.
But a decision on where the subs will be built is not expected until mid-year after the government considers bids from Japan, Germany and France.
The opposition wants to see more details, especially on troop numbers, before offering bipartisanship support.
"We want to look behind that headline and see what is proposed," defence spokesman David Feeney told ABC radio on Wednesday.
Labor was willing to support a "plausible plan" to spend two per cent of GDP for defence spending.
"The challenge has always been for this defence white paper to set out that trajectory," Mr Feeney said.
Mr Feeney was critical the white paper was being released so close to an election, but acknowledged Labor was guilty of the same thing while in government.
Opposition Leader Bill Shorten questioned the timing of the paper's release, noting it was already 12 months late.
"Is this about the defence of the nation or the defence of the Turnbull government," he asked reporters.
Greens leader Richard Di Natale said it made no sense to have arbitrary targets for defence spending while the government was cutting funding for health and education.
The white paper was looking like the sort of "blueprint you would expect from Tony Abbott", he told reporters.
