Zimbabwe's opposition MDC said it would boycott the country's power-sharing government until sticking points have been resolved and a political deal is reached, sparking the biggest crisis since the administration was formed nine months ago, Reuters reported.

Prime Minister Morgan Tsvangirai said on Friday his Movement for Democratic Change would disengage from President Robert Mugabe's "dishonest and unreliable" ZANU-PF party in the country's unity cabinet set up in February.

"It is our right to disengage from a dishonest and unreliable partner. 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 are restored amongst us," Tsvangirai told reporters.

A key test of the MDC's decision may come next month when Finance Minister Tendai Biti -- who is a senior MDC leader -- is due to present Zimbabwe's 2010 national budget.

Mugabe's ZANU-PF said the MDC's move would have to be considered seriously by the party.

"That is a matter that would require a collective response from all of us in the party. It needs some serious consideration. I wouldn't want to pre-empt the party's position," said Didymus Mutasa, a senior ZANU-PF official and Minister of State in Mugabe's office.