Michael Ancram, the shadow foreign secretary, has accused the government of "faffing about" over Zimbabwe, saying that "action" such as economic sanctions and a bar on President Mugabe travelling should be considered.

Ancram's comments came prior to a meeting by the Commonwealth Ministerial Action Group, which was assembling in London on Thursday.

Meanwhile, Jack Straw admitted that the Commonwealth only had limited options and influence over Mugabe, who has been continuing his attacks on white farmers and political opponents in Zimbabwe.

Straw said that international condemnation of Mugabe was swelling and that even Africa was now joining in the condemnation.

However he felt that "very little is going to make Mr Mugabe change his practices".

The foreign secretary said that economic sanctions were not a satisfactory solution to the crisis. "People sometimes talk about economic sanctions. President Mugabe himself has imposed the most severe economic sanctions on the people of Zimbabwe and the peoples of southern Africa," he said.

"Our job is to try to end the sanctions which Mugabe has imposed and then to secure a situation where the rule of law is imposed."

Straw did concede that "the Commonwealth has to do something" to halt the attacks saying it was "on the agenda" for the Commonwealth Ministerial Action Group.

He said he wanted to see international observers in place from the very beginning of the electoral process - adding that the European Union was already addressing the issue and that action could be taken next month.

"The United States is concerned about it, so is the European Union and above all so too are the other countries in Africa, particularly southern Africa," he said.

However, Ancram felt that the foreign secretary's promises were not enough to prevent the demolition of democracy and "the birth of a rogue state".

He said: "It is not good enough to say we are going to make slow progress or, as Jack Straw said, we are going to be watching and monitoring."

The move followed calls for international help by Ben Kahula, an official with the Commercial Farmers Union, who has described watching officials from Mugabe's ruling Zanu PF party splitting open fellow white farmer Duncan Cook's head with a machete.Kahula said: "They have just had the Zanu PF people's congress up at Victoria Falls and it is clear that it is going to be very violent between now and the election itself. Everything is deteriorating rapidly and we hope that the EU, America, Britain and other Commonwealth countries will not neglect us."He added that Zimbabwe's plight had taken a back seat since September 11.

Straw also felt that "Mugabe and the rest of Zanu PF have used the international situation in Afghanistan to get through measures which they might not have contemplated had that not been the case."