The promise, to be made in a landmark speech to the Australian Republican Movement on Saturday, will dramatically reignite debate about whether Australia should have its own head of state.

In a move that will energise republicans and give supporters of an Australian head of state a clear choice between Labor and the Turnbull government ahead of the next election, Mr Shorten will pledge to hold a simple "Yes" or "No" vote.

The question would be: "Do you support an Australian republic with an Australian head of state?"

The promise means a first vote on the issue would be held sometime between 2019 and 2022, to be followed by a second vote after that would settle on the tricky topic of the best model.

Prime Minister Malcolm Turnbull has said the republic debate should not be considered until after the Queen dies. But Mr Shorten will argue the debate does not require Australia to "wait for a change of monarch, we don't need to tip-toe around our future".

"I'm confident Queen Elizabeth would farewell us with the same affection and good grace she has shown every time a Commonwealth nation has made the decision to cut its ties with the monarchy. We can vote for a republic and still respect Queen Elizabeth," he will say.

He will also promise to appoint a specific minister with responsibility for the republic if he wins the next election.

The Labor leader's promise to hold a republic vote will be followed up on Sunday by the unveiling of a major new tax policy that will clamp down on Australians using trusts to avoid paying tax.

Mr Shorten has previously said he would like to see an Australian head of state by 2025.

The Opposition Leader's promise to "take the first real step to an Australian republic in our first term" represents the most detailed road map yet on how his government would advance the issue.

If a compulsory plebiscite of all eligible citizens produced a "yes" vote, a subsequent national debate would then occur on how to choose an Australian-born head of state.

This plan is broadly in line with the Australian Republican Movement's preferred timeline of a plebiscite by 2020 that would ask whether Australia should have its own head of state, and how that person should be chosen. The ARM plan calls for a second referendum on the issue to settle the matter by 2022.

"We cannot risk being caught in a referendum like the last one, where Australians were given one vote to settle two questions. When a lot of people voted 'No' because of the model, not because of the republic," Mr Shorten will say.

"The first, clear question we ask the people should be whether we want an Australian head of state. And the debate should be about why. About our sense of Australia, our history and above all, our future."

In 1999, the Australian Republican Movement - which was then led by Mr Turnbull - was hamstrung by divisions over whether an Australian head of state should be directly elected, or chosen by the parliament or prime minister. The push ultimately failed.

Mr Turnbull has been loathe to reopen the republic debate since becoming Prime Minister given it would trigger conservative divisions within his party. On his recent trip to Britain he declared himself both a republican and an "Elizabethan".

Mr Shorten believes Australia can retain its sporting and cultural links to the Commonwealth even if it voted to leave it.

"We can vote for a republic and recognise that Will and Kate have two seriously cute kids. We can vote for a republic and still binge watch The Crown on Netflix. And we can vote for a republic without derailing the business of government, or the priorities of this nation," he will say.

"I know an Australian republic isn't front-of-mind for everyone, but I don't buy the argument that we can't have this debate until every other problem in the nation has been solved...it's no good hoping for a popular groundswell – we must set a direction and bring people with us, and we have to do it early."

- The Age