This is the heartstopping moment tour boats collided, injuring at least two people in northern Thailand.

Shocking footage shows a motorboat slamming into another vessel while racing across the fog-shrouded water in Chiang Mai on January 1.

One of the boats had veered away to avoid an oncoming vessel - only to speed straight into another one. With the driver unable to steer on time, panicked passengers were seen reclining as they braced for impact.

A couple were reportedly injured in the collision.

Arnon Kulnil, chief of Sri Lanna National Park, said authorities were aware of the incident and will summon the parties involved for questioning.

He said: 'We believe this accident was caused by the boat driver's negligence. Before the area was opened to tourists, the park held meetings and training drills with operators and guides to clearly establish the rules.

'Boats must always travel on the right side, move slowly and cautiously, and use lights when navigating in fog. In this case, the driver appears to have been speeding and not exercising proper care.'

The official said that tour guides and boat operators were required to take care of victims of accidents, while boats are required to undergo safety checks and carry insurance policies.

The park chief added: 'Following the incident, the national park authorities are not remaining idle. We will summon those involved to issue a written warning and demand accountability for the injured tourists, as the park has accident insurance to provide initial compensation.'

Authorities said the dam and surrounding tourist spots have generated more than 20 million baht (473,199 GBP) in just two months, with nearly 2,000 tourists visiting on peak days.

But despite its importance to the local economy, the area may face closure if similar accidents occur, park officials warned.