By Belinda Goldsmith and Thuy Ong
LONDON/SYDNEY (Reuters) - He may still be in nappies but Prince George embarks on his first official tour this weekend as Britain's younger royals ride a wave of popularity that is expected to dampen republican movements in Australia and New Zealand.
The eight-month-old prince, third-in-line to the British throne, will accompany his parents the Duke and Duchess of Cambridge on a three-week tour of the two former British colonies.
His first official event is expected to be at a parent and baby group on April 9 at Government House in Wellington, the New Zealand capital, the residence where his father, Prince William, crawled for the first time during a royal tour in 1983.
William and his wife Kate will also mark a century since the outbreak of World War One by paying tribute to both countries' war dead before leaving on April 25.
Queen Elizabeth, who turns 88 this month, is scaling back her workload and the younger royals - William and his party-loving brother Harry - are taking on more duties as is their father and heir apparent Prince Charles.
Monarchists in Australia said the visit takes place at an interesting time, with Prime Minister Tony Abbott bringing back an oath of allegiance to the Queen when he was sworn in last year and reintroducing the honors of knight and dame.
"There's been a resurgence in young people and popularity with the monarchy in Australia and a lot of that is because there was a generation gap between them and Prince Charles," said Daniel Czech, 28, of the Australian Monarchist League.
"Now William and Harry and Kate are taking on the duties of their father and grandmother, people really respect them."
Following George's birth last July, opinion polls showed record royalist support in Britain, with Queen Elizabeth more popular than at any stage of her 62-year reign - a shift from 1997 when popularity slumped after the death Princess Diana, William and Harry's mother.
The Queen remains head of state of Australia and New Zealand and 13 other former British colonies. Republicans want to end this constitutional monarchy but have failed to stop rising royalist support since the Queen's Diamond Jubilee in 2012.
A ReachTEL poll in February found only 39 percent of Australians now favor a republic, a 20-year low, while in New Zealand the figure is slightly higher at 42 percent.
New Zealand republicans have said little about the visit but said the prospect of a change in New Zealand's flag is a milestone for their own identity.
Prime Minister John Key last month promised to hold a referendum on changing the national flag, which has Britain's Union Jack in one corner, if he wins a third term in September.
Australia ruled out changing its flag and its republicans acknowledge that no change in its link to Britain is imminent.
"It's beyond due but the question is what's the natural time for this to happen and most Australians tell us that the most natural transition point is of course the end of the Queen's reign," said David Morris of the Australian Republican Movement.
(Additional reporting by Gyles Beckford in Wellington, Editing by Angus MacSwan)