National television reported on Tuesday that Mugabe had expressed disappointment with the land use by A2 (commercial) farmers, saying "only 44% of the land distributed is being fully utilised".
"He warned the farmers that government will not hesitate to re-distribute land that is not being utilised," the report added.
Mugabe was speaking at a rural school near his birthplace where he donated 40 computers to four schools in the area.
A government land audit report released late last year showed that some 4.2 million hectares of land had been allocated to less than 200,000 black commercial farmers and ordinary agriculturists.
Zimbabwe embarked on its land redistribution programme in February 2000, compulsorily taking away prime farmland owned by some 4500 white farmers and handing them over to the landless black majority.
Land was siezed from 4500 white
farmers and given to blacks
Before the land seizures, some 70% of the most fertile land in the country was owned by white farmers who were mainly descendants of British settlers.
Of some 4500 large scale commercial white farmers operating in Zimbabwe five years ago, there are about 600 now and own three percent of the country's land. Many have relocated to neighbouring countries and as far afield as Nigeria.
Food shortage fears
In December last year, government officials reported that less than a quarter of planned Zimbabwean land had been put under crop, raising fears of looming food shortages this year.
Harare last month said it had set aside 12 billion Zimbabwe dollars ($1.9m) to buy food aid for some 1.5 million needy Zimbabweans.
The hungry will require food aid ahead of the next main harvest due in April.
Maintaining that the country had enjoyed a 'bumper' harvest in 2004, the government last year said it required no food aid from outside the country.
A combination of factors, including poor planning, lack of resources, HIV/AIDS and drought have led to a huge slump in agricultural production in recent years in the southern African
country, once a breadbasket of Africa and a food exporter.