Taito Phillip Field could find himself demoted by the Prime Minister if the inquiry into the allegations finds he acted improperly.
A minister outside Cabinet, the embattled Labour MP holds the Associate Justice, Associate Pacific Island Affairs, and Associate Social Development and Employment portfolios.
Prime Minister Helen Clark could strip
him of his ministerial roles and send him to the back bench as she has done with other ministers such as Dover Samuels and Lianne Dalziel.
The danger for Labour is if Mr Field becomes disgruntled with his treatment and opts to become an independent MP in Mangere which he holds with an election-night majority of 13,860, the largest in the country.
Although there is no suggestion he is even contemplating that, he would be safe from being expelled from Parliament as the anti-party-hopping law has now expired.
If Mr Field became an independent it would complicate matters for the Prime Minister, who, assuming she leads the next Government after the results of special votes are known, will have to deal with a number of parties in a finely balanced Parliament.
A byelection would be held only if Mr Field resigned or his seat was vacated.
For the seat to be vacated he would either have to be found guilty of a crime punishable by two or more years in prison or be convicted of a "corrupt practice" under the Electoral Act.
But Labour would have a high chance of retaining the seat in a byelection.
According to the Cabinet Manual:
* Ministers must ensure no conflict exists or appears to exist between their public duty and private interests.
* Ministers must conduct themselves at all times in the knowledge that their role is a public one; appearances and propriety can be as important as actual conflict of interest in establishing what is acceptable behaviour.
* A conflict of interest may be financial or non-financial, and may be direct or indirect.
