ACT Party leader John Banks says the National Party will not back any changes to the electoral system that remove its potential support MPs at the next election.
Following a review of the MMP system, the Electoral Commission is recommending the lowering of the party vote threshold to 4% and the scrapping of the rule under which parties that win one electorate seat can bring in additional MPs according to their percentage of the party vote.
Mr Banks told Morning Report the latter proposal is a woeful one based on the weight of political submissions by parties who were happy with the system when it was serving them.
He says the Opposition believes it can win through the back door by removing three or four MPs who might be voted in under the current system in 2014 and who would support a government led by John Key.
Mr Banks says National would not let that happen "for obvious reasons".
Acting Prime Minister Bill English says he's not too bothered by Mr Banks making statements about how the National Party will vote on the proposed changes to MMP.
"He's giving an opinion," Mr English says, "and on these kinds of issues you'd expect him to have a strong opinion - everyone else has."
The Government says it won't be responding until the commission has delivered its final report in October, once public submissions on the recommendations have been received.
Parliament may have to grow?
The Electoral Commission says the size of Parliament may need to be increased to account for the growing population, and to ensure proportional representation is retained.
It warns that if the number of electorate seats grows from the current 70 to 76 because of population growth, the system may cease to be proportional because of the reduced number of list seats.
Chief electoral officer Robert Peden says that while the question of the number of MPs was not part of the review, it is something that may have to be considered in the future.
Too many MPs already - Peters
The New Zealand First party says, however, that there should not be an increase; its leader, Winston Peters, says Parliament already has too many MPs.
"Given that we have sold off so many state assets, we don't need so many members of parliament any more - or ministers for that matter," he says.
"And bear this in mind: the whole of New Zealand is many times smaller than the biggest electorate in Australia. So let's not try and make out that the job is too difficult.
"The original Royal Commission way back when this whole change in our electoral system was first mooted said that we could live with a hundred [MPs]."
Green MP Holly Walker says most people want the seat issue removed, but that raises other problems. If it happens, she says, then wider consideration needs to be given to reducing barriers to entering Parliament.
