President Robert Mugabe's government has warned it will arrest white Zimbabwean farmers resisting evictions from new land targeted for black farmers, state media reported on Wednesday.

Critics say Mugabe's controversial seizures of productive commercial farms from hundreds of whites and low output from new farmers has plunged the southern African state into a severe economic crisis in the last seven years.

Industry and union officials say about 600 of Zimbabwe's 4,500 white farmers have kept their land after the sometimes violent grabs by Mugabe's supporters.

But the government handed some of them eviction notices earlier this year or reduced the size of their properties.

Veterans of the 1970s war of liberation invaded white-owned commercial farms in 2000 with the backing of the government, which went on to appropriate the land.

The seizures set it at odds with the West, and the resulting disruption to farming has been widely blamed for Zimbabwe's food shortages.

More than 4,000 white commercial farmers have lost their properties under the reforms. Last year authorities passed a constitutional amendment barring former owners from challenging the seizures in court.

The official Herald newspaper said on Wednesday some farmers who were given notices three months ago to wind up their operations risk being arrested for resisting eviction after the expiry of the 90-day notice period.

The daily quoted Minister of State For Security Didymus Mutasa, who is also responsible for land reform and resettlement, as saying that the government would move against the farmers accused of going to court to delay their departure.

We have a list of farmers resisting eviction ... and we are going to act accordingly to redress the situation, he told a meeting attended by senior government officials.

Mutasa was not immediately available for further comment.

Zimbabwe, once a net exporter of grain to southern Africa, has suffered food shortages over the last seven years as its farming sector has been hit by drought and disruptions linked to the land seizures.

On Wednesday, the Herald reported that the head of the state grain marketing agency (GMB), Samuel Muvuti, said Zimbabwe was negotiating with several southern African countries to import more maize to boost national grain reserves.

But he gave no further details.

The United Nations Food and Agriculture Organization and World Food Programme said last month more than four million Zimbabweans, about a third of the population, would need food aid this year.

Food shortages are part of a wider economic crisis, also seen in the world's highest inflation rate of over 4,500 percent, unemployment above 80 percent and rising poverty.

Mugabe, in power since independence in 1980, says the seizures are designed to correct injustices committed under British colonialism and to economically empower Zimbabwe's indigenous black majority.

Zimbabwe