Zimbabwe's central bank has revalued its dollar again, cutting another 12 zeros off its currency in a bid to tame hyperinflation and avert economic collapse.

Reserve Bank of Zimbabwe Governor Gideon Gono said: "This Monetary Policy Statement unveils yet another necessary programme of revaluing our local currency, through the removal of 12 zeroes, with immediate effect."

Mr Gono gave no updated inflation figures but said broad money supply growth rose from 81,000 per cent in January to 658 billion per cent in December.

The last time inflation was officially recorded in mid-2008 it had soared to 231 million per cent.

Meanwhile, constitutional changes are being pushed through Zimbabwe's parliament to pave the way for a power-sharing government between President Robert Mugabe and the opposition, Movement for Democratic Change (MDC).

Mr Mugabe and MDC leader Morgan Tsvangirai signed a pact to form a unity government last September to try to end a post-election crisis, but a dispute over control of ministries delayed implementation of the deal.

On Friday, the MDC agreed to join the government.

Justice Minister Patrick Chinamasa said a constitutional bill creating the post of prime minister for Mr Tsvangirai would be introduced in parliament on Wednesday.

He said once passed, it would, on the following day, be transferred to the senate where it is expected to be approved.

Mr Chinamasa said the government was working to a timetable set down by regional Southern African Development Community (SADC) leaders at a summit on Zimbabwe last week, which called for the formation of the unity government by Feb. 13.

The new government has raised hopes of rebuilding Zimbabwe's shattered economy, where food and fuel is in short supply and unemployment estimated at 94 per cent.

Africa's deadliest cholera outbreak in 15 years has also hit the country, killing over 3,100 people and infecting another 60,000.

South Africa and the African Union (AU), ahead of a summit of the continent's leaders in Ethiopia, called for the US and Europe to immediately lift sanctions on Zimbabwe.

© Independent Television News Limited 2009. All rights reserved.