Prime Minister John Key, currently in China, has paid his respects to Margaret Thatcher.
The former UK prime minister died overnight after suffering a stroke.
He said it was a sad day for Great Britain, and described Lady Thatcher as a "fiercely determined woman".
"The passing of Margaret Thatcher is obviously a very sad day for her family and for Great Britain," says Mr Key.
"She will be remembered as a very strong and determined leader that faced some real challenges – obviously the conflict with the Falklands, the conflict with the IRA and tremendous economic challenges that Great Britain faced."
Lady Thatcher was 87.