Grieving relatives of 24 Chinese tourists who died in a bus inferno in Taiwan have demanded answers from authorities, after the worst road accident ever to hit mainland visitors.

The first group of 46 relatives arrived in Taiwan Thursday to identify the bodies of their loved ones, and many broke down in tears as they visited a funeral parlour where the victims's bodies are being kept.

Emotions were high at a briefing hosted by Taiwanese officials, with distraught relatives demanding to know the cause of the tragedy and questioning why no one was able to escape when fire ripped through the bus.

"The relatives demanded the truth and asked about the rescue process. Some of them wanted Chinese experts to take part in the investigation," said Tang Wen-chi, a Tourism Bureau official who attended the late night meeting Thursday.

"Why is there no truth after so many days? Why can't we find anyone to take responsibility?" Taiwan's United Daily News quoted unnamed relatives as saying.

The report said some relatives questioned whether the low cost of the tour had increased safety risks, as drivers for such tours reportedly often work over-time, leading to fatigue.

The price for an eight-day around the island tour, tailor-made for Chinese tourist groups, typically costs less than Tw$20,000 ($625).

The bus was just a few kilometres away from Taipei's Taoyuan airport, for passengers to catch a flight home Tuesday, when it was engulfed in flames and careered through an expressway barrier, killing all 26 on board, including a Taiwanese driver and guide.

Investigators are probing the cause of the accident and say the fire started at the front of the bus, near the driver's seat.

Questions are still swirling over why no one was able to escape via the emergency exits.

Chinese officials have demanded Taiwan take measures to ensure the safety of mainland visitors to the island, after a number of fatal accidents involving tourists from China in recent years.

"Relevant government agencies are taking measures to review and improve travel safety to ensure that similar accidents will not happen again," said tourism official Tang.

Since the accident authorities have increased inspections of tourist buses and tour operators will be fined if safety doors are not working.

Liu Kezhi, secretary-general of China's Association for Tourism Exchange across the Taiwan Straits, expressed "strong dissatisfaction" over the accident Thursday.

Chinese media has also warned of a decline in tourists to Taiwan.

"If Taiwan does not seriously reflect and improve, Chinese tourists would be playing with their lives if they go there again," Huanqiu.com said in an editorial.

Tourism from China to Taiwan boomed for eight years under Beijing-friendly president Ma Ying-jeou who left office in May.

But since new leader Tsai Ing-wen, a Beijing-sceptic, took over ties have become increasingly frosty.

Taiwan's official data showed the number of Chinese tourists dropped 16 percent in May-July 2016 compared to the same period last year, with speculation Beijing is putting pressure on Tsai through squeezing tourism.