Taiwan has accused China of using "dollar diplomacy" to persuade Nauru to switch diplomatic recognition from Taipei to Beijing.
It also claims the decision was not fully supported in Nauru.
President Rene Harris announced in Hong Kong that the nation had severed ties it established with Taiwan in 1985 and signed a communiqué to set up diplomatic relations with Beijing.
Taiwan's foreign ministry spokeswoman Chang Siao-yue claimed not everyone in the Nauru government was happy with the switch.
The French news agency, AFP, quoted Ms Chang as saying she understood that cabinet members were planning an emergency meeting.
Ms Chang also claimed that Beijing had lured Nauru, which is suffering a financial crisis, with a 60 million US dollar grant and had guaranteed to help the nation settle a loan worth 77 million US dollars with General Electric in the United States.
She accused China of not being sincere about efforts to help Nauru develop.
But she said Taipei was not going to fight back by launching a money race with Beijing.