Berlin  - Germany warned Wednesday that Zimbabwe's new unity government faces huge challenges, after the swearing in of opposition leader Morgan Tsvangirai as prime minister.

German Foreign Minister Frank-Walter Steinmeier welcomed Tsvangirai's appointment, but pointed to the huge economic and health challenges facing the impoverished country.

"Huge tasks lie ahead for the new unity government, " Steinmeier said, adding that Zimbabwe "urgently needs a new beginning, and more than anything the people need an improvement in their humanitarian and economic state."

Tsvangirai's inauguration ends five months of bickering between his Movement for Democratic Change (MDC) and Mugabe's Zanu-PF party over the implementation of a September power-sharing accord.

The long-time opposition leader will be responsible for the formulation and implementation of government policy. Mugabe, 84, remains head of state and government.

"From Robert Mugabe and his party in particular I expect them to keep to their agreements, so the country's problems can be tackled with determination," Steinmeier stressed.

The foreign minister called for the new government to "lead Zimbabwe back to the path of democracy and respect for human rights."

"It is clear," Steinmeier added, "that we will measure the new unity government by its deeds."

Thousands of Zimbabweans have died of cholera in recent months, mostly for lack of clean water, and around 7 million cannot adequately feed themselves.

Nine-digit inflation has rendered the national currency effectively worthless. dpa