Former Labour MP Carmel Sepuloni says she will decide by Monday whether to proceed with an electoral petition after losing the Waitakere seat to National's Paula Bennett.
Ms Bennett has retained Waitakere by nine votes on a judicial recount, and Ms Sepuloni is thus out of Parliament.
Ms Bennett won the seat on election night by 45 votes, lost it by 11 last weekend when official results were announced and now has it back again.
Ms Sepuloni says it's highly unlikely she will go through with an electoral petition seeking legal scrutiny of every aspect of the election process, but she will take advice this weekend.
Her loss allows list MP Raymond Huo to return to Parliament so that Labour keeps the 34 MPs its party vote entitles it to.