African mediators are expected in Zimbabwe on Thursday in a bid to break the deadlock in the country's power sharing government.
The party of Morgan Tsvangirai, the prime minister, stopped attending cabinet meetings earlier this month, but since then, the MDC says government-instigated violence has increased.
Farm workers displaced by President Robert Mugabe's "settlement" policy say they are some of the people being physically abused.
Manfred Nowak, the UN's special rapporteur on torture who is expected to travel to the capital Harare to investigate the allegations, told Al Jazeera: "I am concerned about the current political crisis.
"It's always with these kind of fact-finding missions that I want to speak to all sides, but it is up to the government to decide who in will be willing to speak to me and provide his or her side."
Haru Mutasa reports.
Source: Al Jazeera