HARARE: Zimbabwe Prime Minister Morgan Tsvangirai on Friday suspended cooperation with President Robert Mugabe's "dishonest and unreliable" camp but said he will not quit the unity government.

The snub, the biggest threat to the fragile partnership since it formed eight months ago, was sparked by the renewed detention of Tsvangirai's top aide Roy Bennett, who stands trial for alleged terrorism Monday.

"It is our right to disengage from a dishonest and unreliable partner," the Movement for Democratic Change (MDC) leader told journalists in the capital.

"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, who joined his old rival Mugabe in power in February, nearly a year after disputed polls, said the action against Bennett showed "the fiction of the credibility and integrity" of the pact with the 85-year-old president.

"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.

The MDC will not resume relations until all outstanding issues are resolved and the unity pact is fully put in place, Tsvanagirai said Friday.

"Should this constitutional crisis escalate, then the self-evident solution would be the holding of a free and fair election to be conducted by (regional bloc) SADC and the AU (African Union) and under UN (United Nations) supervision."

While suspending relations with ZANU-PF, the MDC 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-time 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.

Bennett's detention ahead of his trial next week also prompted sharp criticism from Western powers, which called for an end to what they said was harassment of Tsvangirai's supporters.

Washington on Thursday demanded Mugabe "end the harassment" of the former opposition, including Bennett, while the Swedish European Union presidency, called the court's decision an act of "politically motivated abuse".