New Act leader Don Brash says he would not support a return to the first-past-the-post voting system, although he is not a big fan of MMP either.

A referendum on whether voters wish to retain MMP and, if not, which system they prefer will be held in conjunction with the general election this year. Dr Brash's predecessor, Rodney Hide, was a supporter of first-past-the-post, despite his party's presence in Parliament often depending on MMP.

However, asked which system he preferred, Dr Brash said his personal preference was supplementary member - in which there are more electorate MPs and proportionality applies only to the list seats. Prime Minister John Key also favours the system, which gives a greater chance of one party being able to govern without the need for coalition partners.

Dr Brash said he believed it should be possible for small parties to be represented. Under first-past-the-post in 1981, Social Credit got 21 per cent of the vote but only two seats.

"That doesn't feel quite right in my view, so you do want a way in which small parties can have some representation in Parliament."

He said allowing list seats also allowed people such as himself who did not want to go through the selection process for electorate seats to enter Parliament. Public servants had to give up their jobs to run for office, despite the uncertainty of whether they would actually be elected.

"In 2002, I wouldn't have given up the Reserve Bank governorship on the odd chance I might have got some National Party selection in an electorate."

Dr Brash was formally declared the leader of Act over the weekend and will meet the Act caucus tomorrow to select a deputy leader and decide who should lead the parliamentary team until the election.

Dr Brash will also have talks with Prime Minister John Key about the ministerial posts held by Rodney Hide and John Boscawen. Yesterday, he refused to give his preference for deputy leader, saying it was a matter to discuss with caucus.

Yesterday, Heather Roy contacted the Herald to say she will only put her name forward for the deputy leadership if Dr Brash supports her in it.

Current deputy leader John Boscawen has expressed an interest in keeping the job and becoming the parliamentary leader, as well as staying on as minister.

Speaking on TVNZ's Q+A programme yesterday, Dr Brash also reiterated his belief that the Maori seats should be abolished but said it would not be a bottom line in any future coalition.

"I think one of the things we learned about MMP is not many things can be absolute bottom lines."

Maori Party co-leader Pita Sharples also did not rule out being in coalition with National in the future, even if a new Don Brash-led Act Party was involved.

Dr Sharples said the issue was the relationship with National rather than Act. Currently the issue of the seats is on the backburner - under its agreement with the National Party the Maori Party agreed not to pursue entrenchment of the seats in return for the National Party not moving to abolish them. That agreement meant the issue of the seats was left out of a constitutional review under way.

Supplementary Member
* Of 120 members of Parliament, 90 are electorate MPs and 30 are "supplementary seats" from party lists.

* Voters get two votes: one for the electorate MP and a party vote. The party vote only counts for the 30 supplementary seats. So if a party gets 10 per cent, it gets three list seats plus any electorates it might win.

Mixed-member Proportional
* 70 electorate MPs and about 50 list MPs.

* Two votes: One for the electorate MP and a party vote. The party vote counts for the whole 120 seats. So if a party gets 10 per cent, it will get 12 seats overall including electorate seats. If it gets more electorates than its party vote entitles it to, there is an "overhang" (as with the Maori Party currently).