Non-governmental organisations (NGOs) distributing food aid are being forced to negotiate with the Zimbabwean government after "sporadic" incidents in which security forces impounded relief destined for drought-stricken areas.

"So far, incidents of the interception of food aid being distributed by NGOs can be described as 'sporadic', and we will become more worried if they become persistent," Cephas Zinhumwe, chief executive officer of the National Association of Non-Governmental Organisations (NANGO), told IRIN.

"Individual NGOs such as Care International and NANGO have been, and are still, engaged in initiatives to rectify the issue with the government, to facilitate the uninterrupted activities of relief agencies," he said.

Zinhumwe cited two recent incidents in Masvingo Province, in the south, and the Rushinga district of Mashonaland Central Province, in the north, where the police intercepted relief shipments being transported by NGOs. The names of the affected NGOs were not disclosed.

He said the police had accused the NGOs of attempting to use relief consignments as a way of influencing voters against President Robert Mugabe's ZANU-PF government ahead of next year's presidential and parliamentary elections.

Mashonaland Central is a ZANU-PF stronghold, where party militias regard strangers with suspicion and police allegedly turn a blind eye to complaints of harassment by party loyalists.

The police were overzealous in impounding relief supplies, Zinhumwe said, "but we were heartened by the intervention of the local members of parliament", who, after being approached by NGOs for assistance, ensured that the aid was released.

Zinhumwe said NANGO had dispatched a monitoring team to observe the conditions NGOs were working under, and were awaiting a report on whether other humanitarian organisations had been constrained from operating freely.

"It would be wrong to intercept food aid, considering that the country is currently reeling under poverty and most areas that were affected by last year's poor harvests are facing starvation," he said.

The Food and Agriculture Organisation (FAO) and World Food Programme (WFP) issued a joint report on Zimbabwe's food security in June, in which they predicted that "people at risk will peak at 4.1 million in the first three months of 2008 - more than a third of Zimbabwe's estimated population of 11.8 million."

The WFP assists about 300,000 people a month with food aid, and made an urgent appeal on Wednesday for a further US$118 million to provide 3.3 million people with food assistance from November 2007 to March 2008.

Food aid has been a contentious issue in Zimbabwe for a number of years. The government has accused humanitarian organisations of collaborating with local opposition parties and of being the intermediaries of Western countries opposed to ZANU-PF policies, particularly the former colonial power, Britain, while NGOs and government critics have retorted that ZANU-PF has used state-controlled food supplies as blackmail to extort votes from the electorate.

Lovemore Matombo, president of the Zimbabwe Congress of Trade Unions (ZCTU), told IRIN, "It is immoral for the government to force NGOs to be accountable to it when distributing much-needed relief. The government is incapable of feeding its own people, and what legitimate role does it have in presiding over the work of professional NGOs?"