Prime Minister Morgan Tsvangirai said on Sunday Zimbabwe should invite international observers and a peacekeeping force to ensure that its next national election is free and fair.

Tsvangirai formed a coalition government with President Robert Mugabe a year ago to end a political and economic crisis, but analysts say mutual suspicion and strategic positioning are delaying democratic reforms meant to clear the way for a poll next year.

Addressing a party rally just outside Harare, Tsvangirai told supporters of his Movement for Democratic Change (MDC) that Zimbabwe could guarantee that violence that has marred previous parliamentary and presidential elections is avoided by accepting observers and a peacekeeping force.

"Let's bring in foreign observers for the next elections ... We can use the African Union and SADC [Southern African Development Community] forces for peacekeeping during the election period," he said.

There was no peacekeeping force in 2008. Mugabe allowed poll observers from SADC and the African Union but refused those from Western countries, saying they were biased against his Zanu-PF party.

"We want a peacekeeping force so that we can have a free and fair election," he added.

Tsvangirai charges that Mugabe -- 86, and in power since Zimbabwe's independence from Britain in 1980 -- has remained in office by using violence and rigging elections, including a 2008 presidential run-off that the MDC boycotted over violence.

Under a global political agreement that brought together Mugabe's Zanu-PF and Tsvangirai's MDC into a power-sharing government, Zimbabwe must free the media sector, write up a new constitution and hold elections in two years, but the whole process is running months behind schedule.

On Thursday, Mugabe said he would stand for re-election if his party nominated him, brushing off calls for him to make way for a younger successor after 30 years in power.