Former prime minister Helen Clark pressured her former ministerial colleague Margaret Shields not to accept the title "Dame".

But the former MP for Kapiti did not buckle, and this afternoon she will be invested as a Dame Companion of the New Zealand Order of Merit.

Dame Margaret is one of the 24 women and 48 men who will be formally installed as dames and knights at a ceremony in Wellington.

Helen Clark's Labour Government replaced the titles in May 2000 with the non-titular honours of principal and distinguished companions of the order.

National restored the titles in March and gave the 84 people affected by the change four months to choose whether to become dames and knights.

Helen Clark sent Mrs Shields a letter setting out why Labour had abolished the titles and saying she hoped she would not accept one.

Dame Margaret described Helen Clark's approach as being asked to "toe the line", but said she did not see it as a party-political issue.

She did not believe that accepting the title meant she was a royalist.

Dame Margaret said she and Helen Clark had agreed to disagree. "I have a great deal of respect for Helen, but I am not a clone."

The only other former Labour MP given the title choice was the former Speaker Margaret Wilson, and there was never any doubt she would reject the title. As Attorney-General, she had presided over the abolition of the right of appeal to the Privy Council.

Helen Clark, now Administrator of the United Nations Development Fund, is in New Zealand on holiday but could not be reached for comment.

But she is understood to have been deeply disappointed that Dame Margaret and some others to whom her Government awarded high non-titular honours had accepted titles.

Dame Margaret - a Cabinet minister for six of her nine years in Parliament and later chairwoman of the Greater Wellington Regional Council - was initially made a distinguished companion in January last year. She was already a companion of the Queen's Service Order.

She said the reason she accepted the title of "dame" was "overwhelming support" from the public and people who had supported her for years.

"They were annoyed when I got the award and no title."

Only 13 people who had the option of becoming dames or knights turned down a title. They included actor Sam Neill, academics Ranginui Walker and Vincent O'Sullivan and authors Patricia Grace, Joy Cowley and Witi Ihimaera-Smiler.

Among those being invested today will be former PM Dame Jenny Shipley, sports heroes Sir Russell Coutts, Sir Peter Snell and Sir Colin Meads, Maori leaders Sir Tumu te Heuheu, Sir Archie Taiaroa and Sir Harawira Gardiner and businessmen Sir Stephen Tindall, Sir Ralph Norris, Sir Peter Maire and Sir George Fistonich.