After four months of delays, Malaysian authorities have cleared for sale a best-selling political biography of former Prime Minister Mahathir Mohamad.

The book, Malaysian Maverick: Mahathir Mohamad in Turbulent Times by Barry Wain, a former editor of the Asian Wall Street Journal, was published in December by Palgrave Macmillan in the UK. A shipment of 800 books sent prior to official publication has been held in Malaysia's Port Klang since November, while the Home Ministry examined the book's contents.

In a letter to the book's Malaysian distributor, the Home Ministry said Malaysian Maverick has been given "clean approval." Mahathir has simultaneously been denouncing the book and demanding its release since December.

Copies are expected to go on sale at Malaysian book shops early next week.

Issued as a hardcover volume as part of an academic series, Malaysian Maverick has sold more than 12,500 copies in Hong Kong, Southeast Asia and Australia. In Singapore, it has been on the Straits Times' best-seller list for three months, with many copies being bought by Malaysians.

Both Palgrave Macmillan and Barry Wain released statements welcoming Malaysia's decision.

"We have always stood by the book, which has been subject to peer review to ensure its academic rigor," said Alexandra Webster, associate director of the publisher's scholarly and reference division. "And we are pleased that the people of Malaysia will now have the opportunity to read it."

Wain, who is currently writer-in-residence at the Institute of Southeast Asian Studies in Singapore, said he was delighted by the news. "We've been waiting for more than four months for the Malaysians to make a decision, and we're extremely pleased they have given the book a clean bill of health," he said.

Wain said Malaysian Maverick has been the subject of intense debate and controversy among Malaysian bloggers, politicians and officials. "Much of the discussion has been ill-informed," he said. "In one case a person reviewed the book without actually reading it."

Several attempts have been made to pirate the book and make it available free online as a protest against what critics feared was government censorship. "Now, Malaysians, like people in every other country, can read the book and make up their own minds about it," Wain said.

Plans are being made to launch the book officially in Kuala Lumpur and Penang, and possibly other Malaysian cities, he added.