A Danish minister told Reuters news agency "that is not acceptable."
Last weekend, a United States official warned that the US may have to take "intrusive" measures to ensure that food aid was properly distributed.
Up to six million people - half the population - are estimated to need food aid after poor rains, combined with the government seizure of almost all white-owned farms.
Bertel Haarder, European Affairs Minister of Denmark, which holds the EU presidency, was sparking at a meeting of EU and Southern African officials in the Mozambique capital, Maputo.
The meeting was due to be held in Denmark but was switched to Mozambique because Zimbabwe's leaders are banned from entering Europe under EU sanctions.
"We would like to strongly react against the fact that the Zimbabwe government is using our aid and our food to put political and economic pressure on its own people," Mr Haarder said.
Maize bags
The BBC's Christian Fraser, who recently went to Zimbabwe, says that bags of maize were stacked outside polling stations during the by-election in Insiza - reportedly put there to reward people who voted for Mr Mugabe's Zanu-PF party.
Zanu-PF won the election in what was considered an opposition stronghold.
Following the US warning, Zimbabwe accused it of planning to invade the country under the pretext of guaranteeing the distribution of food aid.
Mr Mugabe denies that the food crisis is a result of his land reform programme and blames it on a drought, which has affected much of the region.
But white farmers who are prevented from working their land say that their dams are full of water.
Just a few hundred white farmers remain on their land, out of some 4,000 two years ago.
Our correspondent says that the land has gone to Zanu-PF officials, who often have no farming background, instead of the landless black people who were supposed to benefit.
In Maputo, Zimbabwean Foreign Minister Stan Mudenge repeated his government's argument that former colonial power Britain should compensate the white farmers who have lost their land.
As a result of British colonial rule, whites owned much of Zimbabwe's best farmland.
Britain has refused to pay unless there is transparency in the redistribution of land.