BEIJING - A Chinese mainland spokesperson Wednesday denounced Taiwan's move to obstruct extra holiday flights across the Taiwan Strait, saying it was a grave deviation from the humanitarian needs of millions of families and tourists.

"The unreasonable practice of the Taiwan authority impairs trips of tens of thousands of tourists, the get-together of many families, and the feelings of compatriots across the Strait," said Ma Xiaoguang, spokesperson with the State Council Taiwan Affairs Office at a press conference.

Citing security concerns regarding the M503 route, the Taiwan authority refused to approve 176 additional cross-Strait flights operated by China Eastern Airlines and Xiamen Airlines, the most important family gathering festival in China.

The decision is expected to make it difficult for around 50,000 people to return home during the holiday. Additional cross-Strait flights for the festival have been a regular practice since 2008 when direct flights between the two sides began.

"The Taiwan authority linked two totally irrelevant issues together and penalized Taiwanese living on the mainland," Ma said. "It has gone to the length of taking residents and business people from Taiwan as hostages in retaliation against mainland airlines."

"Such a move has seriously compromised the welfare of people on both sides, particularly Taiwanese people," Ma said, stressing that the air route and those connected to it were safe.

The mainland will try every effort to assist Taiwan compatriots in their trip home, Ma said, adding that Fujian Province had increased frequency of passenger liners across the Strait.

A leading official from the International Air Transport Association (IATA) spoke in support of the Chinese mainland operating the M503 route to ease traffic congestion, earlier this month.

"The M503 route, which has been used since March 2015, is not a new route. Its position and design have been approved by the International Civil Aviation Organization," the IATA official said.

Airlines from China's Hong Kong and Macao special administrative regions and southeast Asian countries began flying north to south on the M503 route in March 2015.

The Taiwan aviation authority, however, expressed concern over the start of the south-to-north operation on the route on Jan 4 this year.