Rwanda said on Friday it had proof of an intended major attack by the Democratic Republic of Congo (DRC) and denied it was fomenting conflict inside its neighbour's border.

Kigali and Kinshasa have been blaming each other for renewed instability in east Congo, where Rwandan-backed M23 rebels have seized the regional capital Goma and are advancing on more territory, with hundreds dead and thousands uprooted.

"We categorically oppose the DRC's attempts to portray Rwanda as being responsible for its instability in the eastern DRC," Rwanda's ambassador to the UN in Geneva, James Ngango, told an emergency meeting of the Human Rights Council.

"What is clear, however, is the imminent threat the current situation poses to Rwanda. Following the fall of Goma, new evidence has come to light regarding an imminent, large-scale attack against Rwanda," he said, adding that Kinshasa and its allies had stockpiled weapons in and around Goma airport.

It was unclear if the diplomat considered the threat to be active or neutralised by the M23 advance.

"The weapons were not ... against the M23. Rather, they were pointed directly at Rwanda," he added, saying they included rockets, kamikaze drones and heavy artillery guns.