The prestigious USD 1.4 million award can only be collected by the laureate or close family members.
Liu, a Chinese dissident, is serving an 11-year sentence for subversion after co-authoring an appeal calling for reforms to China's one-party political system. His wife has been under house arrest since the award was announced last month.
Norwegian Nobel Committee secretary Geir Lundestad told The Associated Press that no other relatives have announced plans to come to Oslo for the December 10 ceremony.
"The way it looks now, it is not likely that someone from his close family will attend," Lundestad said.
"Then we will not give out the medal and the diploma during the ceremony." If that happens it will be the first time since 1936, when there was no one present to accept the medal and diploma for German journalist Carl von Ossietzky, who was seriously ill and refused permission to leave Nazi Germany.
However, a representative of Ossietzky received the prize money, Lundestad said.
The Nobel committee has skipped selecting a winner altogether in some years, including during World War II.
Lundestad said the committee has not yet ruled out that someone from Liu's family can attend the ceremony.
"If someone shows up at the last minute, it will not be a problem to change plans," he said.
China has called Liu a criminal and has pressured countries not to send representatives to the ceremony at Oslo's City Hall.
Lundestad said ambassadors from Russia, Cuba, Kazakhstan, Morocco and Iraq have declined invitations, but didn't specify the reasons.
Russian Embassy spokesman Vladimir Isupov said the Russian ambassador would not be in Norway at the time of the award ceremony.
"It is not politically motivated and we do not feel we are pressured by China," he said.
Lundestad said 36 ambassadors have accepted the invitation to the ceremony and 16 ambassadors have not yet replied. Some of them have asked for more time to decide, he said.