Zimbabwe's ruling party has been accused of deliberately withholding aid from opposition supporters in areas facing starvation because of drought.
The country's human rights commission said opponents of President Robert Mugabe's Zanu-PF party had been told they would never get any food aid.
The government has not yet commented.
Mr Mugabe declared a state of disaster in February, with the government estimating that four million people would need food aid by January 2017.
"Ruling party members were the major perpetrators in violations linked to distribution of food," Zimbabwe Human Rights Commission (ZHRC) chairman Elasto Mugwadi told media in the capital, Harare, detailing the findings of the investigation.
Mr Mugwadi said huge numbers of people had been affected by the alleged tactic, without giving exact figures.
The government says half the rural population faces starvation.
In recent months, there have unprecedented protest against the government of the 92-year-old leader, who has now been in power for 36 years.
Analysis: Brian Hungwe, BBC News, Harare
The scathing report on the allegations of the politicisation of food aid in rural areas by senior government officials and public servants lays bare accusations that have long been denied by President Robert Mugabe.
The ZHRC says its findings were a result of extensive investigations across the country.
It will be difficult for Mr Mugabe to simply dismiss the allegations.
The powers of the rights body are enshrined in the constitution, giving it a legal mandate to carry out investigations into human rights violations and to make recommendations to parliament.
The political implications of the report are grave, especially with general elections due in 2018, although similar allegations have been made in the past.
With growing popular calls for electoral reform, there will be many who fear that this investigation betrays the extreme tactics which may be employed to ensure election victory.
Alleged attempts to exert pressure on rural folk by withholding food will be seized on by Mr Mugabe's critics as evidence that his government has reached a new low, especially given the food crisis the country is facing.
Zimbabwe has endured two years of failed rains, with this year's problems linked to the El Nino weather pattern.
Elections are due to take place in 2018.