The call by National candidate Katherine O'Regan for tactical voting against Winston Peters in Tauranga backfired, says Labour candidate Margaret Wilson.

"Katherine, ironically, really helped Winston get in by suggesting people voted for her and not for me," she said.

Mr Peters, the New Zealand First leader, held the seat by 323 votes.

If he wins after special votes are counted, his party gets six MPs. If he loses, it will get none because it polled below the 5 per cent threshold.

Mrs O'Regan was second on 9130 votes - behind the 10,969 she polled last election - and Professor Wilson third on 8597.

Professor Wilson said the national trend was to Labour, not National, and Mrs O'Regan did not have a strong personal following. "National had plateaued and Winston was going down slowly and we were going up slowly."

With one more week, she believes, she would have overtaken Mr Peters.

"The difficulty was to get people to see that in this particular set of circumstances it was Katherine splitting the vote, not me."

Three weeks from the election, Mrs O'Regan tried to persuade Labour voters to back her in the close three-way contest.

Based on a local newspaper poll giving Mr Peters 30 per cent support, Mrs O'Regan said that if 70 per cent did not want him, they should vote for her.

She said after the election that if Labour had cooperated, she would have beaten Mr Peters. But Labour began campaigning more strongly in the last few weeks when it believed it could win.

Supporting Professor Wilson's view is the fact that on Saturday Labour polled highest in the party vote, which National won last time. Labour won 10,347, National 9135 and New Zealand First 4082 in a seat that last favoured Labour in 1935.

Professor Wilson said she had built a base for a strong Labour challenge next time. She was elected to Parliament anyway, through the Labour list.

Mrs O'Regan has missed out by two places on being re-elected from National's list. But if Rangitikei National candidate Simon Power loses his 68-vote majority on special votes, she could still return to the House once Don McKinnon resigns to take up his job as Commonwealth Secretary-General.