Bangladesh's Nobel-winning Muhammad Yunus lost a final appeal on Tuesday against his sacking from the pioneering microfinance bank he founded and reportedly told his staff it was ‘time to leave.’

"The appeal has been dismissed by the Supreme Court," Yunus's lawyer Tamin Husain Shawan, adding that the decision, made by the full seven-member court bench of judges, was unanimous.

The central bank, which is nominally independent from the government, removed Yunus on March 2 on the grounds that he had failed to seek its approval when he was reappointed indefinitely in 1999.

The High Court upheld the order in a March 8 ruling, with judge Muhammad Mamtaj Uddin Ahmed saying the sacking was legal and that Yunus had also exceeded Grameen Bank's mandatory retirement age of 60.

Backed by a high-profile international lobby group, Yunus, 70, defied the sacking order by filing an appeal and continuing to work at Grameen's headquarters.

But after Tuesday's legal defeat, he told staff there that it was time for him to leave and make way for new leadership, a witness said.

"Yunus said 'I went to court to seek justice, but now I have received the verdict and it is my time to leave Grameen Bank,'" bank official Amimul Islam said.

Another colleague, Atiar Rahman, a senior bank officer, said that Yunus ‘told employees he would be happy and relieved if the management of the bank were given to a competent successor.’

Grameen Bank cancelled a planned press conference late on Tuesday because of ‘unavoidable circumstances’, a spokeswoman said.

Supporters say Yunus has been victimised by Prime Minister Sheikh Hasina, who he crossed in 2007 when he set up a political party during a period of military rule.

In December, following the release of a Norwegian TV documentary critical of Yunus, Hasina accused him of ‘sucking blood from the poor’ and pulling a financial ‘trick’ to avoid paying tax.

Having exhausted his personal legal options, Yunus's only hope now resides in a separate appeal lodged by nine elected Grameen Bank board members but few observers expect the case to succeed.

Attorney General Mahbubey Alam said Yunus's legal battle was now over with the dismissal of his final appeal, adding it was ‘highly unlikely’ the Supreme Court's verdict on the board members' appeal would be any different.

"After this verdict by the country's highest court, Yunus's position as managing director of Grameen Bank is illegal," he said.

"There is no possibility of a compromise," Alam said, adding that ‘a person can retire but an institution will not die.’

Grameen Bank's government-appointed chairman, Muzammel Huq said that he would call a board meeting after he had received a full copy of the Supreme Court verdict.

As well as being sacked, Yunus has been vilified in the Bangladeshi press and summoned to court three times in cases nominally connected to Grameen. The bank has become the target of a government probe.

Analysts say Grameen's huge influence in Bangladesh and its move into solar panels, mobile phones and other consumer goods has triggered the government's envy.

His sacking has sparked street protests in Bangladesh and widespread condemnation from overseas, with the US government warning earlier this month that bilateral ties would be affected if an amicable resolution was not found.

Grameen Bank, which is 25 per cent state-owned and employs 24,000 people, provides credit to eight million borrowers, the vast majority of them women living in rural villages.

Its work been copied in developing countries around the world.