THE move by Barbados to become the world's newest republic will trigger calls for other Commonwealth countries to follow suit, a campaign group has said.

Anti-monarchy pressure group Republic said the move by the Caribbean country will provoke more debate about the future of the monarchy in the UK.

Graham Smith, the Republic CEO, said it will show Britain - and other countries with a monarch as its head of state - the alternative to the Royal Family.

On Tuesday, the island nation will sever ties with the Queen by declaring itself a Republic on the 55th anniversary of the nation's independence. 

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Its new ceremonial president, Dame Sandra Madon will take over the Queen's duties.

Prime minister Mia Mottley, who spearheaded the transition, wrote in a speech for Mason last year: “The time has come to fully leave our colonial past behind.

"Barbadians want a Barbadian head of state.

“This is the ultimate statement of confidence in who we are and what we are capable of achieving.”

Speaking ahead of the transition, Republic CEO Smith said: "A huge congratulations to Barbados for this historic moment in their nation's story.

"Barbados isn't just doing themselves a favour, but are showing the way for the other fifteen Commonwealth realms.

"We're already hearing that Jamaica's government wants a review of their constitution next year, and the movement in Australia is again picking up momentum.

"Barbados answers one of the most common questions we hear: what's the alternative?

"The alternative is simple, a parliamentary system with a largely ceremonial head of state."

Smith said Barbados has also shown "how simple" it is to change a constitution, and how smooth the transition can be.

He continued: "The Queen is the monarchy for most people. After she dies the future of the institution is in serious jeopardy.

"Charles may inherit the throne, but he won't inherit the deference and respect afforded the Queen.

"The transition in Barbados has also triggered calls for slavery reparations and an apology from the royals for their family's part in the slave trade.

"Those calls aren't going away and there's no way the royals come out of that debate without significant damage to their reputation.

"The more debate about the monarchy the better as far as we're concerned here in the UK.

"Because the more people take a closer look the more they start looking for a democratic alternative."

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During a ceremony marking the island nation's transition to a republic, the Prince of Wales will highlight what he says are the shared goals and enduring bonds between Barbados and the UK.

Charles will also tell the nation it is “important” for him to attend the event, being staged in the capital Bridgetown, to “reaffirm those things which do not change” as the major constitutional shift takes place.

During the ceremony in National Heroes Square, Charles is expected to say: “As your constitutional status changes, it was important to me that I should join you to reaffirm those things which do not change.”

He will go on to give examples of the ties that will remain, talking about "the close and trusted partnership between Barbados and the United Kingdom as vital members of the Commonwealth” and “our common determination to defend the values we both cherish and to pursue the goals we share”.