The former Christian governor of Indonesia's capital, Jakarta, has withdrawn an appeal against a two-year jail sentence for insulting Islam, according to his family and lawyers.

Basuki Tjahaja Purnama, an ethnic Chinese popularly known Ahok, was found guilty of blasphemy on May 9 over comments he made regarding what he believed to be the misinterpretation of certain verses of the Quran.

At a news conference on Tuesday, Purnama's tearful wife, Veronica Tan, read out a letter in which the former governor 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," he said in the letter, adding that he had dropped his appeal "for the sake of our people and nation".

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

The verdict, which was harsher than expected, triggered an outpouring of anger and support among Purnama's supporters, with many attending a number of protests and candle-lit vigils in cities across Indonesia and abroad, including in Amsterdam, Toronto and Melbourne.

Prosecutors, who had called for a suspended one-year jail sentence, have already filed an appeal against the decision to jail Purnama.

That challenge is still going ahead, and the ex-governor'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," one of the lawyers, I Wayan Sudirta, told the Reuters news agency on Tuesday.

He added that Purnama's legal team had requested his relocation from prison to city or house confinement.

The news came a day after the United Nations called on President Joko Widodo to free Purnama and repeal blasphemy laws which they say undermine religious freedom in the Muslim-majority nation.

"Mr. Purnama's blasphemy conviction and imprisonment will undermine freedom of religion or belief and freedom of speech in Indonesia," a statement from UN experts, who included special rapporteurs on freedom of religion and freedom of expression, said on Monday.

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"We urge the government to overturn Mr. Purnama's sentence on appeal or to extend to him whatever form of clemency may be available under Indonesian law so that he may be released from prison immediately."

The controversy began in September 2016 when Purnama, known for his outspoken style, outraged Muslims when he controversially quoted a passage from the Quran ahead of elections for the Jakarta governorship.

Purnama, Jakarta's first non-Muslim governor for half a century and its first ethnic Chinese leader, had said his political rivals were deceiving people by using a verse from the Quran to say Muslims should not be led by a non-Muslim.

Some saw the message as the then-governor criticising the verse itself, as opposed to those who may misuse it to undermine his political aspirations.

The governor denied the blasphemy allegation but apologised for the comments.

Yet, Indonesia's highest clerical body declared the remarks blasphemous and urged authorities to bring charges, while tens of thousands took to the streets several times to demand his sacking or imprisonment.

His support suffered following those demonstrations and he lost his re-election bid.