An independent poll of voters' intentions indicates Mugabe would command the support of 31% of voters in a presidential election, ahead of rival Morgan Tsvangirai on 19%.

The research was conducted by the US-based pro-democracy group Freedom House.

Tsvangirai's Movement for Democratic Change (MDC) dismissed the results, noting that Mugabe's supporters were outnumbered by voters who refused to declare their intentions. But it is likely to boost the confidence of Mugabe's Zanu-PF heading into elections expected next year.

The Mass Public Opinion Institute polled a nationally representative sample of 1 198 adult Zimbabweans between June 23 and July 7 2012, Freedom House said. When asked who they would vote for if presidential elections were held tomorrow, 31% say they would back Zanu-PF, an increase from just 12% in a 2009 survey. Alarmingly for the MDC, only 19% expressed support for the party, a dramatic fall from 55% three years ago. Other parties registered just 2%.

Some 40% of respondents did not declare their voting intentions, making it hard to draw categorical conclusions.

Asked who they would support in parliamentary elections, 47% of respondents said they would not vote, or refused to indicate who they would vote for. Some 20% said they would support the MDC (down from 38% in 2010) and 31% would back Zanu-PF (up from 17% in 2010).

The results come as a surprise because for years there has been a near default assumption by the MDC, activists and media that Mugabe's 32-year rule was drained of popular support and is sustained only by rigged elections and violence and intimidation. Freedom House's survey implies the 88-year-old could yet make a political comeback and win.

It also resonates with signs of discontent about the MDC's performance in the unity government it formed with Zanu-PF following the disputed election of 2008. The MDC took responsibility for departments such as education and health and has been criticised for slow delivery. Some observers argue that MDC ministers have fallen in love with their official cars and other trappings of power.

Susan Booysen, author of the interim report Change and 'New' Politics in Zimbabwe for Freedom House, said she encountered complaints that the MDC had lost touch with grassroots constituencies, whereas Zanu-PF was still visible and fighting party political battles there.

"I've heard people saying MDC is just not doing work in the constituencies and is spending too much time in the palace," Booysen added. "They're taking for granted they're the crown princes. They are not capturing the desire for change. And there is still a desire for change among people."

The MDC questioned the validity of the study. Douglas Mwonzora, the party spokesperson, said in Harare: "The party respects the right of individuals and institutions to carry out opinion surveys on the views of the people of Zimbabwe from time to time. However, we note that surveys carried out under current conditions are difficult to rely on due to the fact that they are held under conditions of major fluidity.

"We note that a lot of people interviewed refused to disclose their political preferences. This is obviously for fear of intimidation and the violence they have been subjected to by Zanu-PF and its military junta. This margin of terror fundamentally impugns the conclusion that can be derived from this report."

A statement from the party added: "The MDC reasserts that it is still the most popular party within Zimbabwe. That it has had a positive impact on the lives of the people of Zimbabwe since it formed the inclusive government can never be doubted." – © Guardian News and Media 2012