A government notice yesterday showed Mugabe had assigned to his party the ministries for defence, home affairs – which is in charge of the police – and finance, a crucial portfolio for the resuscitation of Zimbabwe's devastated economy.

Mugabe and the main opposition leader, Morgan Tsvangirai, of the Movement for Democratic Change (MDC), have been deadlocked over how to share key ministries and have agreed to call in Thabo Mbeki, the former South African president, to mediate the crisis. Mbeki's spokesman said he would travel to Harare tomorrow.

The cabinet impasse has outraged Zimbabweans who had hoped a September 15 power-sharing agreement would end economic meltdown.

MDC spokesman Nelson Chamisa said it was a "midnight ambush style of attack" and meant the proposed national unity government was now in jeopardy. "This is Zanu-PF's arrogant wish-list that puts the whole deal into jeopardy. It is unilateral, contemptuous and outrageous," he said.

"The MDC totally and absolutely rejects this nonsense. Zanu-PF is taking people for a ride and there is a price for that. It shows that Mugabe thinks this thing is not about power-sharing but is about power-grabbing. We see things differently."

The MDC published its own list, which it said was based on discussions between Tsvangirai and Mugabe on Friday. In it the opposition has control over the ministries of home affairs – responsible for the police – foreign policy, justice and information. Zanu-PF party would retain the Defence Ministry – and thus control over the armed forces – land and mines, it said.

However, the official Herald newspaper said the allocation of ministries had been decided. It said only the finance ministry was disputed. Chamisa dismissed this as "Zanu-PF propaganda".

Tsvangirai is set to hold a political rally in Harare today, where he is expected to make his first public comments on Mugabe's move.

The power-sharing deal allows Mugabe, in power since Zimbabwe's independence from Britain in 1980, to retain the presidency and chair the cabinet. Tsvangirai, as prime minister, will head a council of ministers supervising the cabinet.

Zanu-PF will have 15 seats in the cabinet, Tsvangirai's MDC 13 and a splinter MDC faction, led by Arthur Mutambara will have three posts, giving the opposition a combined majority.

The government gazette said Zanu-PF would be in charge of the foreign affairs, justice and the media and information ministries.

The MDC would take the health, public service, and constitutional and parliamentary affairs portfolios.

Zimbabwe's economy is imploding, with official inflation at a record 231,000,000%, while shortages of food, foreign currency, water and electricity have hit many the hardest. The Reserve Bank of Zimbabwe introduced a new Z$50,000 note yesterday, barely two weeks after launching Z$10,000 and Z$20,000 notes. Zimbabweans will now be able to withdraw Z$50,000 from their accounts daily, enough to buy three loaves of bread.