ALMATY (Reuters) - A banker and former opposition leader who fled Kazakhstan after his bank was nationalised has described fraud allegations against him as a politically motivated attempt to discredit him.

Mukhtar Ablyazov, who has been an outspoken critic of President Nursultan Nazarbayev and was jailed for a year in 2002, was sacked as chairman of top Kazakh bank BTA in February after the government took over most of its shares to prevent its collapse.

Ablyazov, 45, has since left Kazakhstan, joining a handful of Kazakh politicians who have gone into self-imposed exile in recent years after falling out with the authorities. This week prosecutors accused Ablyazov of money laundering and fraud.

"These allegations are baseless and politically motivated. ... This is no more than a crude attempt by the government to discredit anyone who dares to stand up to them," he said in a statement emailed to Reuters by his representative in Britain on Wednesday.

"It was completely predictable that, having engineered the seizure of BTA Bank, the government would seek to give legitimacy to its actions by launching bogus criminal charges against me and other BTA executives."

Last week Ablyazov's cousin lost her job as a member of BTA's board of directors, BTA said in a statement. The Ablyazov case comes at a time of a deepening financial crisis which has sharpened divisions among Kazakhstan's political elite and crippled its once-robust economic growth.

Recession has made people more critical of the government, prompting the opposition to hold a string of small rallies since the start of the year.

The government has denied the Ablyazov case is politically motivated.

Ablyazov's representative refused to reveal his whereabouts.

A founder of a big Kazakh opposition party, Ablyazov was jailed for a year in 2002 on corruption charges. At the time he said that case was politically motivated, and accused Nazarbayev of trying to silence dissent.

Eventually pardoned, Ablyazov mended bridges with Nazarbayev and became chairman of BTA which was once one of the country's most successful banks but which has been hit hard by the crisis.

Nazarbayev has ruled Kazakhstan with an iron fist since 1989 but has been widely popular because of rising incomes and a booming oil-producing economy.