Looming elections in Burma will only be credible if opposition leaders and ethnic minorities can fully participate, the UN’s special rapporteur to Burma has said.

The comment comes as UN chief Ban Ki-moon prepares for a visit to Southeast Asia next week to attend a regional summit and embarking on a four-country tour that will take in China and Thailand. The issue of the 7 November elections are expected to feature high on the agenda at the summit.

Burma’s first polls in 20 years have attracted widespread criticism, not least because the winner of the 1990 elections, Aung San Suu Kyi, is barred from running for office.

Tomas Ojea Quintana, the UN’s chief rights investigator on Burma, said that while “genuine elections call for broad participation”, the likelihood of this happening in the pariah state was slim, with opposition groups and ethnic minorities sidelined.

“These people have a legitimate role to play in these historic elections. An immediate, unconditional release of all prisoners of conscience is necessary for the elections to be credible,” he said in a report made public before its presentation to the General Assembly in New York on Wednesday.

Many of Burma’s volatile ethnic regions, whose history since the end of British colonial rule in 1948 has been pockmarked with low-intensity conflict, are not able to participate. The government has scrapped voting in around 3,400 villages in the ethnic Mon, Karen, Karenni, Shan and Kachin border regions, while up to 500,000 people displaced inside Burma cannot vote.

One Shan leader told AFP that in that state alone about two million people – around 30 percent of the population there – would not get the opportunity to vote.

How far Ban Ki-moon will go to pressure Burma’s neighbours into taking a tougher stance on the election remains to be seen. The Association of Southeast Asian Nations (ASEAN) maintains a policy of non-interference in the domestic affairs of member states, meaning condemnation has been scarce.

He is also likely to come up against stern resistance when he visits Beijing next week, with China’s economic interests in Burma – massaged by the ruling generals – rapidly growing.

“The Burmese need Beijing for international protection, and the Chinese need the Burmese for raw materials, and perhaps more importantly for strategic access to the Indian Ocean,” Burma analyst Maung Zarni told Reuters.

“Whoever comes to power it won’t make any difference … It’s not like the Burmese generals are fond of the Chinese. They are not. It’s basically a marriage of convenience.”