White farmers have called for foreign intervention to stop Zimbabwe becoming "another Kosovo" as the country's president Robert Mugabe defended his farm seizure policy at a Southern African development conference in Malawi.

Farmer's wife, Vanessa Nicolle, has made an appeal for the international community to step in as she warned Zimbabwe stood "on the brink of anarchy".

Nicolle, a UK citizen, who with her husband Vernon breeds racehorses and grows maize, soya bean and wheat on their 7,500-acre farm, accused the authorities of backing farm invasions by squatter gangs armed with "guns, knives and metal rods".

"The police just stand by while women are being attacked. You can't do anything to restrain them or you get beaten and arrested by the police for inciting violence," she said.

Nicolle claims that squatters are being paid by Mugabe's ruling Zanu PF party in an orchestrated campaign to drive whites from the country.

"There's millions of acres of land in this country which could be developed for African farmers who want to farm. The farms that they've taken they've just given to Zanu PF ministers or to their families," she said.

Predicting that the number of farmers leaving Zimbabwe could soon become an exodus, the "utterly devastated" Nicolles have vowed to leave if attacked by squatters and predicted economic chaos if productive white farmers are driven from the country.

"As soon as the squatters come, we're in the truck and we're out of here and we're never coming back. Where is the sense in effectively shutting down a commercial farm that's growing wheat that makes bread to feed the country, that's propping up an exhausted economy?" she said.

Nearly 90 families in the volatile north-west of Zimbabwe abandoned their farms and fled squatters, who style themselves as veterans of Zimbabwe's war of independence.

Nine white farmers have been killed and almost 100 farm workers injured in the escalating violence. More than 20 white farmers have been arrested because of the clashes and charged with inciting public violence.