Five ships working in the Cromarty Firth have been targeted by lasers in the last six weeks.
One worker even had to seek medical help after the beam was shone directly into his eye.
All of the beams originated from the Black Isle side of the water, and the Cromarty Firth Port Authority is now pleading with the perpetrators to stop.
Harbour master Torquil Macleod last night branded the green lights a “serious health and safety risk” to staff and others using the water.
And a north MSP branded the incidents “simple assault” and called for strict sentences for anyone caught misusing them.
The spate of incidents have been reported to police, who are now investigating.
The first happened on June 13 at about 9pm, when a contractor working onboard a vessel that was undertaking maintenance work on a port authority buoy off the south sutor near the mouth of the firth.
He reported seeing a green light which caused irritation in his left eye which had to be checked by a doctor.
The contractor believed the light to have been a laser.
Four subsequent incidents have occurred in the same area, and have included lights being shone into the bridges of vessels travelling into the Cromarty Firth.
It is believed that each time, the laser was being beamed at ships from the higher land above Cromarty.
Mr Macleod said people could be shining lasers at what they think is open water – but warned that the issue is becoming a major safety risk.
“This is now becoming a serious problem for staff and contractors in the port,” he said.
“People using laser pens may think they are just shining them into the open waters and it is harmless.
“But the port operates 24 hours a day, so even in the dark people are often working in the firth.
“Unfortunately these pens are now causing serious health and safety issues for our staff, customers and contractors.
“We hope this appeal will serve as a warning to members of the public who use these gadgets.
“We would urge them to use laser pens with the utmost care and not to shine them into the waters of the firth.”
It is the latest in a list of highly publicised incidents involving lasers pens being beamed at vehicles in and around the Inverness area.
The Inverness-based coastguard helicopter Rescue 951 has been targeted several times, including an incident where a beam was shone into the cockpit as it carried out a low altitude search for a missing man in the River Ness.
Passenger planes coming into land at Inverness Airport have also been affected this year.
John Finnie MSP said: “On one level this is simple assault and on another a potentially serious matter of public safety.
“I would hope the authorities would use all means to trace the culprit or culprits and hand down suitable sentences.
“There’s far too much of this kind of conduct and it causes significant risk, not just to the individual but to the wider public as well.”
Cromarty Firth councillor Martin Rattray added: “I think it’s very irresponsible and there is the potential for an extremely serious outcome.
“A bit of common sense is required. Whoever is behind it needs to think about what they’re doing and why they’re doing it.
“If something serious were to happen with a ship if it can’t make safe passage then how will these people live themselves if someone gets hurt?”
Police have previously described the misuse of laser pointers as “extremely reckless” when they’ve been directed at aircraft.
A spokeswoman said: “Police Scotland would urge people in possession of these type of devices not to misuse them and reminds people that it is a criminal offence taken very seriously by both Police Scotland and the Scottish courts.”
Mr Macleod urged anyone who know anything about the incidents to call the police, or the port on 01349 852308.
