A packed train derailed inside a tunnel in eastern Taiwan on Friday with authorities confirming at least four passengers appeared to be dead when rescuers arrived.

"Around four people are without life signs," the Central Emergency Operation Center said in a statement, adding rescuers were trying to get to four carriages inside the tunnel that were badly damaged and difficult to access.

A brief video released by the centre inside the tunnel showed rescuers arriving on the scene and one twisted carriage door.

At least 15 people have been sent to hospital, the centre added.

Taiwan Railways Administration issued a separate statement saying "many" were without signs of life, citing the local fire department.

The accident occurred on Taiwan's eastern railway line around 9.30am (0130 GMT) near the coastal city of Hualien.

The eight-car train was making its way from Taipei to the southeastern city of Taitung and was carrying some 350 passengers, the rescue centre said.

The accident occurred at the start of the busy annual Tomb Sweeping festival, a long holiday weekend when Taiwan's roads and railways are usually packed.

Taiwan's eastern railway line is usually a popular tourist draw down its dramatic and less populated eastern coastline.

With the help of multiple tunnels and bridges, it winds its way through towering mountains and dramatic gorges before making its way down Huadong Valley.

aw/jta/jah