Zimbabwe's President Robert Mugabe has vowed that seizures of white-owned farms would not be stopped despite the formation of a new inclusive government.

"There are farms which have been designated in accordance with our land acquisition laws and offer letters given to the new farmers, let not the original owners of the farm refuse to vacate those farms," Mugabe told thousands gathered to celebrate his 85th birthday.

An offer letter is the document given to successful applicants who have applied to take over farmland.

"We are not going to listen"

"We are not going to listen to the excuse that some farms went to the SADC (Southern African Development Community) tribunal. That's nonsense. We have our own courts here.

The land reforms have been blamed for the food crisis in the former grain exporter as some of the beneficiaries of the land reforms often lacked the skills and means to farm.

The predominantly white Commercial Farmers Union (CFU) says there has been an upsurge over the past weeks in farm invasions by militant supporters of Mugabe's party.

Mugabe said new land owners must follow the law and give the original farmers time to wind up their operations.

"On our side we must also act properly," he said. "The original owner must be given time to wind up but winding up must not be year in year out."

The country's new Prime Minister Morgan Tsvangirai has called for an immediate stop to the farm invasions while his Movement for Democratic Change (MDC) has expressed concern over the farming disruptions.

Mugabe said the new unity government with former rival Tsvangirai's MDC and a smaller faction of the opposition would join forces to repair the country's economy so battered by inflation that the local dollar has been rendered unusable.

"Through the inclusive government we hope to unite to push with renewed vigour in various sectors, the development programmes aimed to raise those sectors," Mugabe said.

"It's not the work of one side. It's the work of all. We hope we shall in this co-operative way manage to bring about some appreciable turnaround of our economy."