Vietnamese officials say a Friday night concert to mark the anniversary of Chinese and Vietnamese diplomatic relations has been postponed because of an unexpected electrical issue.

Many people on Facebook had urged the government to cancel the performance as it coincides with China's takeover of Vietnam's Paracel Islands by force 44 years ago.

Cultural ministry spokesman Nguyen Thai Binh says the performance by an artistic group from China's Inner Mongolia Autonomous Region could not go ahead as scheduled because of an unexpected electrical issue at the landmark Opera House in central Hanoi.

Vietnam's Ministry of Culture, Sports and Tourism and the Chinese Embassy organized the concert.

Binh declined to say whether the postponement was connected to the sensitive timing but said officials from both countries were working to reschedule it.