WELLINGTON: New Zealanders will soon get to vote on whether to change their national flag, which many view as a hangover from a colonial past.

Prime Minister John Key on Tuesday announced plans to hold a referendum within the next three years. His political opponents indicated they would follow through with those plans even if they oust Key in this year's general elections.

The nation's current flag depicts the Southern Cross star constellation in red and includes Britain's Union Jack flag in the top left corner. Many complain it is too similar to Australia's flag and doesn't reflect New Zealand's independence from its former coloniser, Britain.

But many who have served in the military oppose a change. And among those who do favor a change, there is plenty of debate about what would make the best replacement.

Key said he favors a silver fern set against a black background. Some say that would associate the flag too much with sports teams, who often use it, and is reminiscent of a pirate ensign.

In his speech Tuesday, Key said the current flag represents a past era.

''The flag remains dominated by the Union Jack in a way that we ourselves are no longer dominated by the United Kingdom,'' he said.

He pointed to Canada's 1965 decision to ditch the Union Jack in favor of its distinctive maple leaf design as a good example.

''Fifty years on, I can't imagine many Canadians would, if asked, choose to go back to the old flag,'' he said.

He added that a change in the flag would not signify an end to New Zealand's constitutional ties to the British monarchy or its participation with the Commonwealth group of nations.

Don McIver, national president of the Returned and Services Association (RSA), said he doesn't think New Zealanders feel strongly about changing their ensign.

''The view of the RSA is there is no need to change the flag,'' he said.

''Thirty-two thousand New Zealanders have given their lives under the flag and many more thousands have served under it in a combat environment.''

Key said he plans to convene a group of lawmakers from across all political parties to come up with the best process to hold a referendum before the 2017 elections.