Zimbabwe's election authority is fighting a court ruling that allows a jailed opposition MP to run in parliamentary elections this month.
Bennett says he was provoked by a racist verbal attack
Roy Bennett, who is one of three white Zimbabwean MPs, is serving a one-year sentence for assaulting a minister during a debate in parliament.
An electoral court judge last week found Bennett met all the criteria to stand as a candidate from prison.
But President Robert Mugabe said his government would contest the decision.
The electoral court had also ruled that the vote should be put off until 30 April in the eastern district of Chimanimani, where Bennett won a seat in the 2000 elections, so he could campaign.
Bennett, 48, is one of the most prominent candidates of the Movement for Democratic Change (MDC), the largest opposition party.
Mr Mugabe, who branded the ruling "stupid", said the country could not be "held ransom by a man who is in prison".
Bennett's farm has been confiscated by the government under a scheme to give white people's land to poor blacks.
A spokesman for the MDC, Paul Themba-Nyathi, said the party was "shocked" by the appeal from the Zimbabwe Electoral Commission - allegedly an independent body.
"It places [the commission] in an invidious position regarding its neutrality in this election," he said of the appeal.
Meanwhile, the MDC has chosen Bennett's wife Heather to stand in his place in the Chimanimani constituency in the elections scheduled for 31 March.
Bennett's sentence was decided by the Zimbabwean parliament, which has the authority to impose prison sentences on MPs.