People "will turn vigilante" against those visiting second homes in Wales during the coronavirus lockdown, a councillor has said.
Gareth Williams, who represents Botwnnog in Gwynedd, said "feelings are running incredibly high" and he was worried locals would take action.
He said he was reporting 10 to 15 cases a day of people arriving at such homes.
Carl Foulkes, chief constable of North Wales Police, urged people not to take the law into their own hands.
Mr Williams said he "honestly believes" locals could turn vigilante.
But Mr Foulkes said some second and holiday homes were being used for legitimate purposes by key workers, and urged anyone worried about issues relating to Covid-19 to contact them.
"I know of some where workers from utility companies are staying, for example," he said.
"It's important that people don't try to take the law into their own hands.
"We have extra officers on patrol this weekend to ensure the rules are respected. Call us if you know of anyone breaking them, and we'll look into it."
Mr Williams said people were arriving at night to avoid police.
"The worry is that it's not going to clear... the virus isn't going to go away," he added.
"Tensions are very high at the moment.
"I've got to say the police are working very hard, but their hands are tied… if they can stop them on the road when they're on the way to the Llyn Peninsula then they've got the power to turn them round and send them home.
"But unfortunately the problem we've got is once they've reached their second homes the police can't send them away."
He called for police to be given more powers, especially in the run-up to Easter weekend when he expected visitors "in their tens, in their hundreds", adding it was "unbelievably worrying".
"The police need to be able to knock on doors and say 'listen, you've ignored the guidelines'... I think we need to take a stern approach to it."
Meanwhile, Pembrokeshire Tourism has taken to social media to remind people that travelling to to a second or holiday home is classed non-essential travel and illegal under current restrictions.
It said: "You must stay at your primary residence and under no circumstances should you or others attempt to travel to a second home/holiday home, not even to 'self-isolate'. The law is very clear on this."
The Welsh Government said the message to stay at home to save lives was clear.
"We have introduced new powers for the police to protect the public and keep people safe and we will consider introducing further measures if found to be necessary," a spokesman said.
The UK government said visits to second homes were not included in essential travel and police forces across Wales had powers to enforce the rules.