By Grant Ferrett BBC Africa editor

Special affairs minister John Nkomo told the BBC that in some areas 60% of the land allocated to black, small-scale farmers had not been taken up.

Thousands of white-owned farms have been seized by the government and given to black farmers.

About five million Zimbabweans need food aid because of huge shortages, partly blamed on the land policy.

Some black farmers cannot afford to run the farms

Land redistribution is the policy on which President Robert Mugabe and his government have staked their reputations over the past three years.

It has dominated their political agenda and been the centrepiece of two election campaigns.

But the hastily implemented scheme, referred to by the government as fast-track land reform, has been beset by serious problems.

Farms 'empty'

The land seizures were marked by violence and repeated court defeats for the authorities.

Now, the ruling party chairman and special affairs minister has told the BBC that even when farms have been acquired, many of the intended beneficiaries have failed to resettle the land they had been allotted.

"In some cases, the percentage of people who took up the farms that they were allocated has not been encouraging.

"In some cases you have almost 40% of people who were allocated the land who've taken up the land."

Mr Nkomo blamed funding problems, saying resettled farmers had difficulties in obtaining loans from banks.

Flawed policy

The reality is that the government's controversial policy was poorly planned and implemented from the beginning.

Some of those allocated land had little or no experience of commercial farming.

Others had no desire to move from their homes.

Those who did move often did so with minimal support, sometimes unable to afford even to pay for seed or fertiliser.

The upheaval has contributed to two years of severe food shortages which have left millions of Zimbabweans dependent upon emergency aid.

Nonetheless, President Mugabe and his ministers maintain that land redistribution has been a success and that, in time, it will produce bumper harvests.