The newly-appointed vice president, the front-runner to succeed President Hu Jintao, told a group of visiting Japanese journalists that the referendum defeat showed a lack of support for Taiwan's 'splittists,' Kyodo News said.
The vote showed that 'independence and splittist activities' in Taiwan 'could not win people's hearts,' Mr Xi was quoted as saying.
'The maintenance of peace is the shared wish of people on both sides' of the Taiwan Strait, Xi said.
Two referendums held in Taiwan on Saturday on joining the United Nations failed to meet the 50 per cent turnout threshold needed to validate any result.
The referendums were held alongside Taiwan's presidential election won by Ma Ying Jeou, who favours closer ties with China.
Mr Xi did not comment on Mr Ma's election, Kyodo said.
Taiwan lost its UN seat to Beijing in 1971 and is now recognised diplomatically by just 23 countries.
China considers Taiwan, where the mainland's defeated nationalists fled in 1949 after losing the civil war, as part of its territory awaiting reunification, by force if necessary. -- AFP