The Namibian government has taken the first steps in its plan to acquire white-owned farmland.
Critics fear a repeat of Zimbabwe's land seizures
At least three farm owners are reported to have received letters asking them to enter into negotiations for the purchase of their land.
Earlier this month President Sam Nujoma said some "racist" farmers had been mistreating their black workers.
Namibia has hosted advisers from neighbouring Zimbabwe to help plan the redistribution of farmland.
The notices sent to a small number of farms on Wednesday said: "You are cordially invited to make an offer to sell the property to the state and to enter into further negotiations in that regard. In the light of the seriousness of the matter, I shall appreciate it if you would react within 14
The BBC's Frauke Jensen in Namibia said the government's intention was to agree on a price for the farms - but if the two sides could not agree, the government would probably expropriate the land and compensate the farmers unilaterally.
The heading on one letter, to the owner of Ongombo West farm near the capital Windhoek, referred to the "intended acquisition" of the property, according to The Namibian newspaper.
The letter was signed by Hifikepunye Pohamba, the minister of land.
Almost half of Namibia's land, including the best arable plots, are owned by about 4,000 mostly white farmers.
The government has been trying to redistribute land to black people to undo the legacy of the colonial era.
Since independence in 1990, the government has purchased 118 farms in a willing-buyer, willing-seller programme.
But Mr Nujoma has said the government will begin expropriating some white farms.
Critics fear a repeat of the land seizures in Zimbabwe, in which whites have been forced off their farms, often by the use or threat of violence.
Mr Nujoma is a close ally of Zimbabwe's President Robert Mugabe.
The Namibian Agricultural Union (NAU) has convened
an emergency meeting for next week.
Jan de Wet, president of the NAU, said it was
"extremely important that the process is handled in such a way that it does not destabilise the country".
He said the NAU would deal with each case "within the
framework of the law and the constitution".