A growing number of motorists have had a problem getting into their own car after parking on the north side of Lakeside Joondalup shopping centre.

The reason behind the spate of bizarre incidents that have affected dozens of drivers parked near Chemist Warehouse in recent days is baffling.

Mitchell Kingston says his wife found herself in a tricky situation on Thursday as she tried to get into her car using her keyless entry device, which usually disables a car’s immobilizer without the need for a key.

“Once she got back to her car, she could not get back in,” he said.

“Her car and keyless entry and ignition connection had been completely disconnected.”

She contacted a local Ultra Tune mechanic who managed to get her moving again and she inquired if this was a common occurrence.

“He (told her) in the last week there had been days where 20-plus car alarms in the area would start going off and people were locked out of their cars,” Mr Kingston said.

“They had helped over 100 people regain control of their car and the drivers were told to move out of the area and park elsewhere so it didn’t happen again.”

Mr Kingston said he returned later in the day to thank the mechanic and it happened again - he witnessed the mass alarms going off for himself.

“I called Lakeside Joondalup and they said to me the matter has been given to the police as there is a hacking device in the car park somewhere,” he said.

Joondalup Police said they were aware of the issue but ‘no evidence of criminality’ had been identified.

Lakeside Joondalup posted a statement on its Facebook page on Friday morning, saying that WA Police don’t believe suspicious activity is involved.

However, shopping centre management has increased security patrols in the area where most of the reports are coming from.

The Australian Communications and Media Authority has told the centre’s management the cause of disruption could be as simple as an internet modem.

Or could it be a doorbell?

A similar incident occurred in 2017 on a section of street in the Melbourne suburb of Carlton. Cars were being towed because people suddenly couldn’t get into them.

But when they reached the mechanic, no problem was found.

An investigation found a constant signal at the same frequency as car key remotes was interfering.

The culprit turned out to be a faulty doorbell at a dentist on the street.

Ultra Tune Joondalup’s Gary Bourne told 6PR his staff had been helping people out since Tuesday last week but he had no idea about the cause.

“We’ve physically helped 40 or 50 people unlock their cars and we’ve been contacted by at least 100 people,” he said.

After the first case, Mr Bourne said his own staff had been affected by the issue.

“That night we went to leave the building ourselves and we couldn’t get into our own cars,” he said.

Several readers have confirmed that the problem has been going on since at least last week.

Kim Pou said last Friday she pushed the button on her key after returning to her car and was surprised when it didn’t work.

“So I used the key to manually unlock and my alarm went off,” she said.

“I was locked out for about 25 minutes before I actually managed to get into my car.

“I honestly thought maybe my key needed a new battery so I went and got that all changed.”

However, Lijo John said it couldn’t have been a battery in his case - he was driving a brand new car.

“I was unable to access my car near Chemist Warehouse last week,” he said.

“My remote access just wouldn’t work and it’s a brand new car. I had to use the manual key, which set the alarm off and I couldn’t disable it for a while.”