A police helicopter was targeted at 10pm on Monday, April 21, while it was searching for culprits responsible for a series of laser attacks.

This incident didn't last long, police said, and the pilot was not harmed.

On January 22, commercial aircraft and cars were targeted by laser pointers in Merrylands and Pendle Hill.

The crime manager at Holroyd police, Sergeant Paul Roe, said catching those responsible was difficult for police.

``The [lasers] aren't big, they're hand-held [devices] and it's difficult to see where they're being pointed from,'' Sergeant Roe said.

``Pilots can only narrow it down to a suburb ... we live in the hope that [the culprits] will continue to shine it up so we can locate them.''

Sergeant Roe said police relied on information from the community.

Lasers are readily available online. A website claims lasers can `` pop balloons, cut through plastic, light a match and cigarettes''. Low-powered lasers start at $3 while ``military-grade'' lasers range from $300-$3000.

Lasers are used for legitimate purposes including astronomy, surveying, mining and construction.

The State Government last week announced it would ban powerful laser pointers, and carrying them without a legitimate reason could incur a maximum jail term of 14 years.

David Mutton, a senior lecturer in the school of psychology at the University of Western Sydney, believed many culprits pointed lasers at aircraft to ``take a risk''.

``Young people take risks to cause danger, shock and alarm to themselves but in this case it is different because there's no risk of danger to them,'' Mr Mutton said. ``I liken it to those who throw things from overpasses. They have the attitude of `let's see what happens'.

``I don't think in the back of their minds they want to cause death and mayhem. They don't think of the outcome, the bigger picture. It's a feeling of `what can I do to cause fear and alarm?'''

Parramatta's art installation, Flock, suspended over Church Street, will remain turned off after a laser used in the artwork hit traffic reporter Vic Larusso's helicopter on Wednesday night.

Parramatta Council acting general manager Sue Coleman said ``lighting physicists'' were used when Flock was created ``to make certain there were no hazards to aircraft''.

The council will check the installation.