Jakarta's former governor, a Christian, will withdraw an appeal against his controversial jailing for insulting Islam in Muslim-majority Indonesia, to allow prosecutors to appeal the sentence and calm protests, his family and lawyers said on Tuesday.

Basuki Tjahaja Purnama, an ethnic Chinese popularly known as "Ahok", was jailed on May 9 for a longer-than-expected term in a ruling that critics fear will embolden hardline Islamist forces to challenge secularism in Indonesia.

At a news conference, his tearful wife, Veronica Tan, read out a letter in which Purnama thanked supporters and those who were praying for him, or sending flowers, letters and books.

"I know this is not easy for you to accept this reality, let alone me, but I have learned to forgive and accept all this," the former governor said in the letter.

"It is not right to protest against each other in the process I am going through now," he added, saying he was concerned that his supporters could be involved in clashes with parties opposing him.

There have been frequent protests by supporters of the former governor in cities across the world's largest Muslim-majority country and by Indonesian students and workers abroad, following the verdict.

The fortunes of the once hugely popular Purnama turned last September, when he was seeking re-election. He said his political rivals were deceiving people by using a verse from the Koran to say Muslims should not be led by a non-Muslim.

Purnama denied the blasphemy allegation but apologized for the comments. Hardline groups drew hundreds of thousands of protesters onto the streets of Jakarta, however, demanding he be sacked and jailed for insulting Islam's holy book.

His support suffered following those demonstrations and he lost his re-election bid. His trial, which began late last year, drove religious tension in Indonesia to its highest in years.

Purnama's two-year term was harsher than the suspended sentence the prosecution sought, prompting warnings that Islam is creeping into the politics and judiciary of the secular nation.

Purnama's lawyers said withdrawing his appeal could give prosecutors space to appeal.

"We don't want to intervene with the prosecution. They can go ahead," said one of the lawyers, I Wayan Sudirta, adding that Purnama's legal team had requested he be moved from prison to city or house confinement.

It would not be the first time prosecutors had appealed against a tougher sentence than sought in the indictment, said another of his lawyers, Teguh Samudera.

Head prosecutor Ali Mukartono could not immediately be reached for comment.