Zimbabwe Prime Minister Morgan Tsvangirai said Friday he was suspending cooperation with President Robert Mugabe's "dishonest and unreliable" Zanu-PF party but will not quit the unity government.

"It is our right to disengage from a dishonest and unreliable partner," Tsvangirai told journalists after the revoked bail of his top aide Roy Bennett sparked fresh doubt over the fragile eight-month unity pact with Mugabe.

"...until such time as confidence and respect is restored amongst us"

"In this regard, whilst being in government we shall forthwith disengage from Zanu-PF and in particular from cabinet and the council of ministers until such time as confidence and respect is restored amongst us," he said.

Tsvangirai said the arrest and detention of Bennett, his pick as deputy agriculture minister, had shown "the fiction of the credibility and integrity" of the power-sharing arrangement with Mugabe.

"It has brought home the reality that as a movement we have an unreliable and unrepentant partner in the transitional government," he said.

Tsvangirai scrapped a ministerial meeting on Thursday after a magistrate's court revoked Bennett's bail and ordered him to stand trial for terrorism next Monday, in a move which drew sharp criticism from Western powers.

The feisty white former coffee farmer, whose land was expropriated under Mugabe's land reforms, was originally arrested an hour ahead of the swearing in of the new government on February 13.

His case has become a symbol of the unresolved challenges facing the partnership amid claims of a crackdown against Tsvangirai's supporters and disputes over key posts.

While suspending relations with Zanu-PF, the Movement for Democratic Change leader said his party will remain in government as it was the "only one with the mandate to remain".

"For that reason this party for now will not renege on the people's mandate, however it is our right to disengage from a dishonest and unreliable partner," he said.

Tsvangirai and his long-term rival agreed to the unity government nearly a year after disputed polls, which saw Mugabe handed the presidency in a one-man run-off, plunged the country into deeper economic and political crisis.