Jailed former opposition leader Anwar Ibrahim said he does not bear a "personal vendetta" against former prime minister Dr Mahathir Mohamad or current Prime Minister Najib Abdul Razak.

"I have already forgiven everyone a long time ago.

"My battle is not a personal one; it is about institutional reforms. I have no personal vendetta against Mahathir or Najib," Anwar said to Channel News Asia at the Kuala Lumpur High Court yesterday, where he appeared as his own counsel in a defamation suit.

Last February, Anwar was convicted of what he claimed to be a trumped up charge of sodomy, and was sent to the Sungai Buloh prison to serve his five-year sentence.

In 1998, then deputy prime minister, he had been fired and jailed after falling out with Mahathir, who was prime minister at that time.

However, earlier this month, Anwar had stated his support for Mahathir and urged opposition parties and NGOs to support the Citizens' Declaration initiated by his former boss.

A number of prominent figures, from both sides of the political divide, as well as from civil society, had signed the declaration in their personal capacity calling for Najib's removal as prime minister and for institutional reforms.

Najib had been plagued by financial scandals since last year, involving his brainchild 1MDB and the RM2.6 billion deposited in his personal bank account.

He has consistently denied wrongdoing in the matter, saying the deposit was a political donation.

Early this year, the attorney-general had announced that he would not be pursuing charges against Najib after reviewing the investigation papers by the Malaysian Anti-Corruption Commission.