Julia Gillard and Tony Abbott have laid wreaths at the Australian War Memorial to mark the start of the parliamentary year.

The prime minister and opposition leader laid the wreaths at the Tomb of the Unknown Soldier in the Hall of Memory.

It was a symbol of the nation's respect for Australian service men and women who have given their lives in war and in peace, war memorial director Brendan Nelson said in a statement.

"The symbolism of both our political leaders laying a wreath at the Tomb of the Unknown Soldier at the start of the parliamentary year is potent," Dr Nelson said.

"We are reminded that governments and parliaments make decisions that have a price - ultimately the lives of Australian service men and women."