No one was injured and damage was 'minor' in the accident on the tarmac, an SIA spokesman said yesterday.

About 420 passengers were on board the two Boeing 777s, which were preparing for take-off from Changi Airport at around 1.10am.

'Investigations are under way as to the cause and the pilots of both planes are assisting in the investigations,' said the spokesman.

'It is too early to identify the cause, but SIA is cooperating fully with the Ministry of Transport to identify any and all the factors involved in this incident,' she added.

The ministry told The Straits Times that it was investigating the accident. It did not provide further details.

An SIA spokesman said the wingtips of the jets 'came into contact' while both were taxiing at low speed.

She added that the damage to both planes was 'minor' and the safety of passengers and crew on board the two aircraft was not compromised.

Passengers on board the two planes - flights SQ 366 headed for Rome and SQ 352 headed for Copenhagen - were transferred to other SIA planes.

Their journey was delayed by about three hours.

A veteran pilot, speaking on condition of anonymity, told The New Paper that such accidents are rare, given the size of the planes and the number of people on the lookout, from pilots to ground crew.

He had heard of very few similar accidents in his 20 years as a pilot.

He said: 'There have been close calls but even so, not with SIA aircraft and not at Changi Airport.'

Several things could have led to such an accident, he said.

The air control tower could have given the wrong instruction to one of the pilots.

The pilots could have misheard instructions from the air control tower.

This is not the first time an SIA plane has had such a brush.

In 2005, a stationary SIA plane's wing was clipped by a Thai Airways jet bound for a runway at Bangkok's Don Muang Airport. No one was injured but the incident caused the wing of the Thai plane to crack.

According to media reports in April 2005, two SIA pilots were suspended pending an ongoing inquiry by the Singapore and Thai authorities.

theresat@sph.com.sg