By AUDREY YOUNG political editor

If National won a byelection in Pakuranga it might also get former Maori list candidate Hekia Parata elected to Parliament.

A byelection will be held if maverick National MP Maurice Williamson resigns.

On the basis of its 20.93 per cent of the vote last election, National is entitled to 27 MPs. If a present list MP is elected to a constituency, the next person on the last election's party list fills the 27th spot - in this case former Wellington Central candidate Mr Parata.

National's two prime candidates for a byelection are Auckland-based list MPs Don Brash, the finance spokesman who lives near the Pakuranga electorate and has been told to find a constituency next election, and Pansy Wong, who might also appeal to Pakuranga's large Asian population.

Both say they have given no thought to a byelection, but others around Parliament are discussing it as a distinct possibility if, as expected, Mr Williamson is expelled from the party.

The only way to avoid that is for Mr Williamson to make a grovelling and sincere apology to the caucus and party, which is unlikely.

Tolerance for Mr Williamson ran out when he ruined the party's annual conference in Christchurch last weekend with criticisms.

Many believe expulsion would result in his resignation and re-seeking of an electorate mandate to remain in Parliament.

It is unlikely that National could get him thrown out of Parliament through the anti-party hopping law, the Electoral Integrity Act, without Mr Williamson having consistently voted against National.

The act requires that an MP disturb the "proportionality" of the last election before a party leader can write to the Speaker to have the rebel deemed to have resigned.

Decisions about a byelection may be some time away. The caucus vote is scheduled for next Tuesday and the party's board of directors meets two days later.

Lengthy legal action may ensue.

Act deputy leader Ken Shirley said if there was a byelection, he expected Act to contest it.

"It's a key electorate for us. We've always done particularly well in Pakuranga and we'd expect to do well again."

There has been speculation that Mr Williamson might stand for Act, but that would be highly unlikely.

Williamson's options

* Makes a grovelling apology to the caucus and the party and is forgiven.

* Expelled from National - continues as an independent, unchallenged by National to the next election.

* Expelled from National - continues as independent but is challenged under Electoral Integrity Act for condemning and/or voting against the party.

* Expelled from National and resigns, forcing a byelection.