'If this modest wave of liberalisation continues, they may even get fitting rooms.'

"Mr Kashgari...can hardly expect a fair trial if returned." Christopher Wilcke, Human Rights Watch Photo: Reuters

HUMAN rights groups have appealed to Malaysia not to send a young Saudi writer back to Saudi Arabia where he risks execution after he posted Twitter messages considered insulting to the prophet Muhammad.

Interpol has been accused of abusing its powers after Saudi Arabia used the organisation's red-notice system to get Hamza Kashgari, 23, arrested when he arrived at Kuala Lumpur airport on Thursday.

Kashgari, a newspaper columnist, fled Saudi Arabia on February 7 after posting tweets on the prophet's birthday that prompted more than 30,000 angry responses.

One of the fictitious conversations between him and the prophet read: ''I have loved things about you and hated things about you and there is a lot I don't understand about you … I will not pray for you.''

The day after the tweets, a Saudi religious body declared him am apostate and clerics called for him to be charged with the offence, which is punishable by death under Islamic law.

Kashgari tweeted apologies as campaigns on Twitter, Facebook and YouTube drew thousands of supporters demanding his execution. Saudi Arabia has executed people for the offence in the past.

Christoph Wilcke, senior Middle East researcher at Human Rights Watch, said although clerics in Saudi Arabia had called for Kashgari to be tried, they had already decided he was an apostate who must face punishment.

''The Malaysian government should not be complicit in sealing Mr Kashgari's fate by sending him back,'' Mr Wilcke said.

Malaysia's Home Affairs Ministry said in a statement: ''The police are now in contact with the Saudi Arabian authorities in order to determine the next steps.''

Malaysia and Saudi Arabia do not have a formal extradition agreement but have close ties.

Muhammad Afiq Muhammad Noor, a lawyer acting for Kashgari, said he and officials of the United Nations refugee agency had sought access to him without success. He is believed to be held at an immigration centre in Kuala Lumpur.

Mr Wilcke called on Malaysia to allow Kashgari to travel to any country of his choice. ''If Mr Kashgari is not presumed innocent, he can hardly expect a fair trial if returned to Saudi Arabia,'' Mr Wilcke said.