Ghana on Thursday said that it fully backed Zimbabwe's suspension from the Commonwealth after controversial presidential polls and decried treason charges levelled against main opposition leader Morgan Tsvangirai.

Foreign Minister Hackman Owusu Agyemang said that Accra totally supported a Commonwealth decision to suspend Zimbabwe for a year.

"Basically we are taking a principled stand," he said, adding Ghanaian observers sent to Zimbabwe had reported the lack of a "level playing field" and of "criteria or international standards for free and fair elections."

Longserving Zimbabwean President Robert Mugabe was declared the winner of the March 9-11 poll by a wide margin over chief rival Tsvangirai, who immediately cried foul.

"We as members of the Commonwealth stand by the decision which suspends Zimbabwe," the foreign minister said. "We are not saying that Zimbabwe should be ostracised but there is a need for negotiations."

Agyemang deplored the treason charges laid against Tsvangirai, the Movement for Democratic Change leader, who appeared in court Wednesday to face allegations he plotted to kill Mugabe.

The state's action "has the potential of throwing everything overboard but we are hoping that the due process of the law will be followed," he said.

"Basically the Commonwealth needs to speak to the Zimbabwean government to try and encourage the two opposing factions to talk to each other and accomodate each other."

Agyemang said that Ghanaian President John Kufuor was "in constant touch" with Mugabe and Nigerian head of state Olusegun Obasanjo to try and defuse the political tension in Zimbabwe.

The US this week added six Mugabe associates to a travel ban against members of his party and government, bringing to 26 the number of Zimbabwean officials, including Mugabe, who are now barred from the US.