Berlin  - A dissident Chinese author has so far been denied an exit visa to travel to Germany for a literary festival this week and the Frankfurt Book Fair, a Berlin official said Tuesday.

Liao Yiwu had been invited to Asia Pacific Week in Berlin and next week's Fair, said Bernd M Scherer, head of the House of Cultures of the World which organizes the literary event in Berlin.

But although he has a Chinese passport, his exit permit had not been forthcoming. German intellectuals voiced outrage.

"It looks as if he will not be taking part. But we will keep pressing for him to be allowed to come," said Scherer, who had booked Yiwu for panel discussions this weekend.

Yiwu's most recent book describes the fate of "underdogs" in Chinese society and those disadvantaged by change.

Other critical Chinese intellectuals have also faced obstacles in the run-up to the Book Fair, where China is to be the special guest.

Last month, a Chinese official delegation briefly walked out of a pre-fair symposium in Frankfurt in protest at dissidents taking the podium.

Ai Weiwei, a Beijing architect and artist who has celebrity status in Germany and is currently undergoing medical treatment in Munich, has said he will skip the fair because he needs to recuperate, a newspaper, the Sueddeutsche Zeitung, reported.

Ai, 52, was treated for blood clot on the head that he traces to a beating by security officers in Sichuan province.

"Of course it is a great pity he will not be at the Fair. But it is more important that he gets better," said Thomas Minkus, a fair spokesman.

A Munich art gallery where an exhibition of his art opens Monday said doctors ordered Ai to rest up.  dpa