Under the law Taito Phillip Field is innocent until proven guilty and therefore retains his seat in Parliament.
Police said today they were seeking leave from the High Court to proceed with 14 bribery charges against Mr Field.
Under the Electoral Act, MPs seats can be declared vacant for a number of reasons.
This includes conviction for a crime punishable by imprisonment for a term of at least two years.
It does not matter if the MP is sentenced to a lesser term, or not imprisoned at all, if the crime of which the member is convicted carries a possible sentence of two years' imprisonment, the seat becomes vacant.
Mr Field is facing 14 charges under section 103 of the Crimes Act, each of which carries a maximum prison sentence of seven year.
The section in question reads:
"Every member of Parliament is liable to imprisonment for a term not exceeding seven years who corruptly accepts or obtains, or agrees or offers to accept or attempts to obtain, any bribe for himself or any other person in respect of any act done or omitted, or to be done or omitted, by him in his capacity as a member of Parliament."
If Mr Field is convicted of any of the offences the Speaker declares the seat to be vacant.
As Mr Field is the electorate MP for Mangere a by-election would be held.
This would not take place if the conviction occurred within six months of this Parliament expiring or if the Prime Minister declares there will be an election with six months.
The last possible date for the next election is November 15 2008.
If a conviction does take place close to the election, then a resolution passed by a majority of 75 per cent of the House can direct no by-election take place.
In the past by-elections have also been postponed by special legislation.
The last time this occurred was in 1987.