Chinese artist and fierce government critic Ai Weiwei Friday lost his appeal against a multi-million-dollar tax fine on a company he founded, his lawyer said.

Pu Zhiqiang said the Beijing Chaoyang court had rejected the appeal against a tax fine levied on Fake Cultural Development Ltd, a firm Ai founded but which is legally registered to his wife.

Ai, who spent 81 days in secret detention last year as police rounded up dissidents amid online calls for Arab Spring-style protests in China and is still not allowed to leave the country, was barred from attending the hearing.

Chinese artist Ai Weiwei walks inside his home on the day of his court hearing in Beijing on July 20, 2012. Chinese artist and fierce government critic Ai has lost his appeal against a multi-million-dollar tax fine on a company he founded, his lawyer said.

Speaking at his studio in Beijing, he told reporters he was "very disappointed" by Friday's ruling.

"China keeps telling other countries they are a rule of law country... But we only hope they implement the laws they themselves drew up," he added.

Fake argued at its appeal hearing last month that the Beijing tax bureau had acted illegally in fining the company. But Pu, speaking by telephone, said the court had ruled that "their behaviour was legal, their procedures were legal".