Jailed former opposition leader Anwar Ibrahim is puzzled by Umno's fear of his partnership with Dr Mahathir Mohamad.

"I am not sure why the Umno leadership considers my cooperation with Mahathir as something odd because we have been enemies for so long.

"I have explained that I wholeheartedly accept Mahathir's readiness to establish a friendship, in the spirit of kinship.

"I am confused as to why Umno is so afraid of my partnership with Mahathir," the PKR de facto leader said in a statement this afternoon.

Mahathir and Anwar had put aside their decades' long animosity after a meeting in court in September 2016.

Both are now leaders of Pakatan Harapan, with Mahathir as its chairperson and Anwar as its de facto leader.

Mahathir, who is Harapan's prime minister candidate, would also be contesting in the May 9 general election under the PKR logo.

PKR was founded by Anwar and is headed by his wife Dr Wan Azizah Wan Ismail.

Meanwhile, Anwar said his cooperation with Mahathir is driven by their desire to bring about change as Malaysia is plagued by corruption and abuse of power.

The former opposition leader is barred from issuing statements from prison, and his lawyer Latheefa Koya had been barred from meeting him as a result of past statements issued under his name.

Anwar is serving a five-year prison sentence for a sodomy conviction and is scheduled to be released on June 8.

He has claimed that the charge was fabricated by his political rivals but the authorities have denied this.