Four injured survivors of a bus tragedy in Chiang Mai, nine days ago, are scheduled to arrive at the Changi International Airport in Singapore late this evening.

They will be accompanied by a doctor and medical officer from Thailand.

Chiu Travel Sdn Bhd general manager Terence Yung said the injured victims are Tan Yang Soon, 64; Ng Too Hiyok, 63; Lum Jia Miem , 21, and Teo Tien Chor, 59.

"They are expected to arrive here (Batu Pahat) about 7pm and will be transferred to the Pantai Hospital Batu Pahat for follow-up treatment," he told reporters at the Chiu Travel office today.

Meanwhile, Yung said four more survivors were undergoing treatment at the Bangkok Hospital in Chiang Mai and were waiting for their medical reports before being allowed to return to Malaysia.

They are Goh Bak Chai, Ker Shin Hui, Lim Guat Huay and Lim Ah Gek.

Yung said Goh had a crack on his rib cage and needed to wait for it to heal before he could return home.