Prime Minister Malcolm Turnbull says there are more urgent issues confronting Australia than the push to become a republic.

Opposition Leader Bill Shorten has renewed his pledge to the republican cause, echoing state premiers and chief ministers who this week signed a declaration calling for the country to become a republic.

Australian of the Year David Morrison also used his acceptance speech yesterday to voice his support for the movement, saying it was time to revisit the issue.

But Mr Turnbull said it was his personal view that the best time to renew the campaign would be after the Queen's reign.

He said he did not want to repeat the failed 1999 referendum campaign that he spearheaded.

"If you don't want to have another heroic defeat, and you want it to be carried, the best time to do that will be after the end of the Queen's reign," he said.

"Really, what we'll have to see is whether there is enough popular momentum, whether it really becomes a front-of-house issue, a key issue as it was in the late 90s."

Sorry, this video has expired PM says republic push not a pressing issue for Australia

Mr Turnbull said the push would not succeed if it was seen to be a political movement, stressing the need for grassroots support.

"It is not something that a government can just do, even if it wanted to," he said.

"I can't stress enough that this is a decision for the Australian people ... I have no doubt in the future there will be another referendum, and the matter will be decided, as it should be, by the Australian people.

"But the timing of that referendum has to be right."

Mr Shorten has accused Mr Turnbull of backing away from the debate.

Speaking in Melbourne today, he said that Australia "should not have to wait for a change of monarch to renew the republic debate".

Mr Shorten said it was important that Australian citizenship be a prerequisite for the role.

"The only qualification you should need to be our head of state is the piece of paper you hold in your hands today," he said, in reference to the thousands of people attending citizenship ceremonies today.

"Now, for the first Australia Day in our history, the leaders of both major parties are avowed republicans.

"So today I say to the Prime Minister, let us work together to seize the moment, to lead the movement for change.

"Let us have the courage to match our words with actions."

Mr Shorten made similar remarks in his 2015 Australia Day address, when staunch monarchist Tony Abbott was prime minister.