Diplomatic isolation and stepped sanctions are the key to stopping Zimbabwe President Robert Mugabe's tyranny, Democratic Alliance foreign affairs spokesman Tony Leon said on Thursday.

Briefing the media at Parliament on DA foreign policy, Leon was critical of the both the South African government and the Southern African Development Community's efforts to resolve the Zimbabwe crisis, labelling the latter organisation a "toothless bulldog".

He told journalists Zimbabwe needed to hold properly convened, internationally certified national elections.

"You cannot use flawed electoral outcomes as the basis for a post-settlement government of national unity.

"It actually suggests... that somehow democracy is not fit for
Africa, that you can't actually have a democratic election.

"Because if you have an undemocratic outcome, with these post-conflict arrangements such as Kenya and Zimbabwe, you legitimise a stolen or a very flawed electoral process."

Leon's remarks come as South Africa prepares to host another emergency SADC summit on Zimbabwe.

The summit follows the failure on Monday of talks involving Mugabe and his rival Morgan Tsvangirai over how to share control of powerful ministries under a unity government in Zimbabwe.

"People across the world shake their heads at [South Africa's] continued temporising with Robert Mugabe's tyranny. I would take a much more hard-line approach," Leon said.

Under the protocols of SADC, Zimbabwe should forfeit its membership of the body.

"I think [too] that Zimbabwe should be suspended from the African Union, and I think that the normal protocols of diplomatic recognition should be withdrawn."

Efforts by the South African government and the SADC over the past eight years to solve the Zimbabwe crisis had come to naught. The situation had, in fact, deteriorated massively.

"You've got to take a harder stance... you've got to use coercive diplomacy," Leon said.

Responding to a question on whether South Africa should consider intervening militarily in Zimbabwe, he said "all options should be on the table".

However, he doubted whether South Africa had the military capacity.

"With only 3000 combat-ready troops at any given moment, stretched across the sub-continent [on peacekeeping missions], I think your question is entirely theoretical and hypothetical, because I don't think we could engage in Zimbabwe militarily.

"I'm not sure what the result would be if we did, because the
Zimbabwe defence force is not engaged across the African sub-continent as we are, and quite arguably has more combat-ready troops than we do.

"I think you've got to be careful about committing yourself when your commitments are already over-stretched. But clearly, all forms of pressure need to be used against Robert Mugabe."

Questioned about the possible use of sanctions, he suggested these should be implemented, and then stepped up if necessary.

"I think there should be a reconsideration of sanctions, at the very least applying sanctions that target the leadership and the individuals in the leadership cadre in Zimbabwe... And then I think you should start going down the list. But you've got to start that process."

Leon said government policy towards Zimbabwe over the past eight years involved "vague rhetoric" that was not backed up by action.

"We're now living with the consequences, with cholera outbreaks in South Africa -- a direct export from Zimbabwe -- and our entire international reputation... tarnished very severely by the pro-Mugabe stance we continue to take," he said.