PRESIDENT Robert Mugabe has called British Prime Minister David Cameron "satanic" for considering withholding aid from countries that do not respect gay rights, state media said on Thursday.

"It becomes worse and satanic when you get a prime minister like [David] Cameron saying countries that want British aid should accept homosexuality," Mugabe said in a speech on Wednesday in the mining town of Shurugwi, 300km south of Harare.

"To come with that diabolic suggestion to our people is a stupid offer," he said, according to the state-run Herald newspaper.

At the end of the Commonwealth summit in October, Cameron said that countries receiving British aid should respect human rights, including gay rights.

The issue has re-emerged as Zimbabwe drafts a new Constitution with debate on whether to follow neighbouring South Africa's model and include gay rights in the charter.

Mugabe has for decades ranted against homosexuality and in his latest speech again threatened to punish gay Zimbabweans.

"Do not get tempted into that [homosexuality]. You are young people. If you go that direction, we will punish you severely," Mugabe said

"It is condemned by nature. It is condemned by insects and that is why I have said they are worse than pigs and dogs."

Prime Minister Morgan Tsvangirai, who formed a unity government with Mugabe in 2009, has said that he supports gay rights but that gays should "do their things in private".

More recently he said that the people of Zimbabwe will decide what they want in their Constitution which will clear the way for new elections.

The Constitution process is running more than a year behind schedule with a referendum on the charter expected only next year.