Fifty Kazakhstan's opposition figures have written an open letter to former premier Tony Blair urging him to step down as adviser to their controversial president, Nursultan Nazarbayev.

Published in opposition newspaper Respublika, the letter is titled "Blood on Your Hands, Blair!"

The authors are angry that Tony Blair Associates has been involved in improving the reputation and business links of Kazakhstan, a country rich in natural resources such as gas and oil but with a poor human rights record.

Blair's former chief of staff, Jonathan Powell, and former director of communications and strategy, Alastair Campbell, recently visited the country, according to the Daily Mail.

Over Christmas, police opened fire on an unarmed crowd of sacked oil workers. At least 14 people died and 80 were wounded.

Activist want Blair to resign as presidential adviser immediately.

"It is known that you were an adviser to the bloody dictator Muammar Gaddafi," reads the letter. "The whole world saw with its own eyes that he used weapons against civilians in his country, trying hard to suppress the riots. The bloody scenario of Libya was repeated in Kazakhstan.

"The leadership of Kazakhstan in peacetime opened fire and shot at unarmed citizens," the letter goes on. "Such bloody methods are being used in our country since you became an adviser to President Nursultan Nazarbayev."

"You are an adviser to Kazakhstan's leadership. Why within the last seven months were authorities deaf to the demands of oil workers? And finally, they shot at its citizens?"

"We once again urge you to resign from the position of presidential adviser and to stop co-operating with the criminal regime."

A spokesman for Blair said: "Tony Blair's team have been advising on the Kazakhstan government reform programme. He has had no role in this dispute. But the president has promised an inquiry."