China has faced global calls to give the democracy campaigner the option to get treatment abroad since it emerged.
The legal bureau of Shenyang -- the northeastern city where Liu is being treated -- said in a statement Wednesday the invitation was made "at the request" of Liu's family.
China has faced global calls to give the democracy campaigner the option to get treatment abroad since it emerged last month that he was transferred from prison to a hospital after he was diagnosed with terminal liver cancer.
Beijing has come under fire from human rights groups over its treatment of Liu and for waiting until the Nobel Peace Prize winner became terminally sick to take him out of prison.
But authorities have insisted that the 61-year-old has been getting top-notch care from prominent Chinese cancer doctors at China Medical University No 1 Hospital in Shenyang.
AFP reporters saw several police officers stationed inside the hospital. Nurses at the oncology ward, however, said they could not find Liu's name in the computer system.
Liu was sentenced to 11 years in prison in 2009 for "subversion" after calling for democratic reform. He was awarded the Nobel in 2010, with an empty chair representing him at the ceremony in Oslo.
The invitation of foreign experts came after Chinese President Xi Jinping arrived in Berlin on Tuesday for a state visit and the G20 summit in Hamburg on Friday.
"It seems that the Chinese authorities are responding to international pressure by making such arrangements," Amnesty International's China researcher Patrick Poon told AFP.
But, Poon added, Liu and his wife, the poet Liu Xia, have made it clear that they want him to be treated abroad.
"The Chinese government should respect their wish but not just make arrangements to respond to concerns and criticisms," he said.
The US and German embassies declined to comment.
German government spokesman Steffen Seibert said Monday that Berlin hopes Liu will get "all the medical support he needs" and that a "humanitarian solution for Liu Xiaobo should be the highest priority".
The new US ambassador to Beijing, Terry Branstad, said last week that he would like to see Liu have the chance to get treatment abroad.
Asked whether Beijing would consider sending Liu abroad, foreign ministry spokesman Geng Shuang said all countries should respect China's judicial sovereignty instead of using "individual cases to interfere in China's domestic affairs".
Friends of Liu and his wife fear that the dissident may only have months to live and say the couple has expressed their desire for him to go abroad.
Hu Jia, a prominent activist under house arrest in Beijing, told AFP that Liu's treatment is aimed at reducing the pain and helping him live longer.
"Maybe he can still live for six months. But it is difficult to change the result that a Nobel Peace Prize winner dies due to the persecution of the CPC (Communist Party of China)," he said.
The Shenyang legal bureau said Monday that Liu, whose cancer had spread to other parts of his body, was receiving chemotherapy and the "most advanced" drug to treat liver cancer.
He has also received traditional Chinese medicine "as a supplementary treatment", the bureau said, adding that the family has been "satisfied" with the care he has received and "expressed their appreciation".
Friends of Liu have circulated a photo showing his wife feeding him as he sits next to a hospital bed.
More than a dozen supporters held a small protest in Hong Kong and mailed postcards for Liu.
Albert Ho, a former lawmaker in the semi-autonomous city, said the hospital's decision to invite experts "shows that the Chinese government is quite concerned about its image that they would be subject to accusations that they had maltreated Liu Xiaobo".
But Ho said that it was not enough and that Liu should be allowed to have access to friends and "make a choice of his own as to whether or not he would like to seek medical treatment outside China".