Foreign secretary Jack Straw has accused Zimbabwe's president Robert Mugabe of failing to honour promises to uphold democracy and human rights.

Speaking in the Commons on Tuesday, Straw expressed his "profound concern" over the situation in Zimbabwe as Mugabe loyalists continue to harass opponents ahead of the next presidential election, which is due by the end of March.

"We remain profoundly concerned about recent developments in Zimbabwe, including violence against the opposition, interference in the judicial system, moves to disenfranchise Zimbabweans overseas and labelling journalists as people who have been assisting terrorists," Straw told MPs.

He said that Commonwealth ministers will discuss the situation in December. A teleconference of the Commonwealth ministers' action group would be held next month, followed by a "proper meeting" in January.

Straw also said it was crucial that independent observers were allowed to monitor the presidential poll.

Under the Abuja accord, Zimbabwe has agreed to respect human rights and uphold the rule of law. As part of the deal, the international community has promised finance for a land resettlement programme.

But Straw said Mugabe's refusal to accept independent observers was a breach of the declarations to which he had previously agreed.

"It is clear there has to be significant changes in the arrangements which president Mugabe is willing to put in place for observers to the electoral process, and for the election process itself, if that election is to carry any credibility," Straw said.