Police are investigating four cases of suspicious men in white vans approaching children on Melbourne’s streets.

Detectives said they believed the four reports – which were alarmingly similar – were not linked.

They occurred in the past three weeks in Melbourne’s north and north-east, with the children managing to get away each time.

No suspects have been identified and investigators believe four different men were involved, Acting Superintendent Paul Cripps said.

“There are similarities – being a white van – but at this stage we haven’t been able to establish any links between the offenders,” he said on Thursday.

Most recently on Tuesday, a 10-year-old boy was approached by a man driving a white van on Landscape Drive in Boronia, about 8.30am.

The boy walked away unharmed.

On Monday, a 15-year-old girl was walking along Saxon Street, in Doncaster, when she was approached by a man driving a white van, about 9.40am.

“The man asked the girl to get in the van. The girl ran away to a nearby shopping centre,” said a Victoria Police statement.

The other two incidents were reported in November – one last week and the other the week before.

A 14-year-old girl was approached by a man driving a white van on Spring Street, in Tullamarine, about 5.45pm on 27 November.

The man asked the girl to get inside the van and she ran away to a nearby park.

The first reported incident occurred on November 18 when an 11-year-old boy was walking along Halley Street, in Blackburn.

He was approached by a man driving a white van, about 3.45pm.

“The man told the boy his mum asked him to give him a lift home,” said Victoria Police.

“The boy declined the man’s offer and the van drove away.”

All of the incidents involved “malicious intent” but the children are doing well despite a scary experience for them and their parents.

The approaches were concentrated around schools, prompting police to step up patrols in affected areas and schools to bolster security.

Cripps said the jump in reports of children being enticed into cars was one of the highest priority investigations for the force.

All the men took a “friendly approach” when speaking with the children and used similar language, with slight variations in the descriptions of the vans involved.

“One thing we have to take into account, we are dealing with children so their descriptions aren’t always as accurate as adults’ [descriptions],” he said.

Parents are encouraged to “be alert but not alarmed” and have a discussion with their children about what to do if they are approached.

“We ask parents to talk to their children and tell them what to do in these situations – not to get into vehicles, safety behaviour, speak to their parents, or teachers, report it immediately and let us know about it,” he said.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at crimestoppersvic.com.au.