Ahead of parliament's official return this week, the party leaders joined Prime Minister Anthony Albanese on Monday afternoon for a Last Post ceremony in Canberra.
Political leaders traditionally mark the beginning of parliament's sittings with a visit to the memorial to honour the nation's veterans and the fallen.
Mr Albanese also met with Marshall Islands President Dr Hilda Heine, who also attended the ceremony, at Parliament House.
Speaking at the ceremony, Mr Albanese referenced former prime minister John Curtin's address on Remembrance Day in 1941, highlighting his focus on "peace worth the winning".
"A peace worthy of all the courage, sacrifice and faith that Australians had shown to win it," Mr Albanese said.
"All we have been able to hold on to as a people and as a nation, because of them."
Ms Ley said the nation could not be "lulled into a false sense of security".
"Old truths are being rediscovered as countries wake up to this deteriorating global security environment," she said.
"As parliamentarians, we will be returning to that place across the lake to help navigate our country through a changing world."
Earlier, Mr Littleproud survived an attempt to challenge his leadership of the Nationals after he split up the coalition for the second time since the 2025 federal election.
Ms Ley will likely face a challenge from conservative contender Angus Taylor during the parliamentary fortnight following weeks of speculation.
Polling showing One Nation gaining support at the expense of the coalition has spooked many Liberals and Nationals.
Members of the two parties return this week with the prospect of a longer separation.
Ms Ley and Mr Littleproud will meet on Monday evening to discuss a possible reconciliation after the opposition leader gave the Nationals a one-week deadline to resolve the parties' differences.
Announcing the split in January, Mr Littleproud declared no Nationals members could serve in a shadow cabinet under Ms Ley's leadership.
