The imminent deportations come at a time of increased tensions between Taiwan and mainland China, with Taipei accusing Beijing of "abducting" citizens from countries that do not recognize the island's government.
A group of 13 Taiwanese and 14 mainland Chinese were arrested by Cambodian police last week for internet fraud, immigration officials said.
"We have decided to deport them to China because they all are Chinese. The Chinese side has asked us to wait while they work out whether to send a plane or buy tickets for them," Major General Uk Heisela, director of inspection and procedure at the General Department of Immigration, told AFP Monday.
He said Cambodia refused to draw a distinction between Chinese and Taiwanese as the country adheres to a "One China Policy".
Cambodia is historically one of Beijing's closest allies in Southeast Asia.
In April both Malaysia and Kenya deported Taiwanese nationals to mainland China sparking uproar in Taipei.
Observers see the cases as China putting pressure on Taiwan's new government, which took office in May, as Beijing does not trust the traditionally pro-independence ruling Democratic Progressive Party (DPP).
Taiwan's foreign ministry confirmed the Cambodia arrests and accused Beijing of pressuring Phnom Penh.
"China requested Cambodia to send all the suspects to the mainland as most of the victims in this case are in China, and they obstructed our personnel from visiting the Taiwanese suspects," the ministry said.
The island has sent its representative in Vietnam to negotiate with Phnom Penh, seeking to have the group repatriated to Taiwan instead.
The foreign ministry added that another four Taiwanese had been arrested at the Phnom Penh airport Saturday, but it is unclear whether it is related to the same fraud case.
Taiwan is self-ruling after splitting with China in 1949, following a civil war, but Beijing still sees it as a part of its territory waiting to be reunified.
The island has never formally declared independence.
While Taiwan's new president Tsai Ing-wen has repeatedly pledged to maintain the "status quo", she also has not bowed down to pressure to accept Beijing's definition of cross-strait relations.