Two girls, aged 14 and 17, were arrested on Saturday night about 4pm and have been charged with stealing a motor vehicle.

The 14-year-old remains in police custody, while the 17-year-old has been released on bail.

The driver, believed to be a 15-year-old boy, was seen driving up to 120km/h through Victorian towns, narrowly missing pedestrians and almost colliding with a semi-trailer.

He is one of two people known to police still on the run on Friday night.

Police first spotted the car, which looks to be a BMW, driving erratically in Thomastown about 2pm before it headed to Whittlesea.

The driver stopped for fuel in Kilmore, putting $30 worth of petrol in the car and fleeing without paying.

The two female passengers were arrested after running from the car outside an Aldi supermarket in Kilmore.

Kilmore Police confirmed the teenagers have been taken into custody at Mill Park police station.

The car, believed to be still carrying two males called Michael and John, continued through Lancefield and Heathcote before heading towards Bendigo.

One witness saw police "flying by with their sirens [on]" as the car sped through Heathcote.

The pursuit was called off shortly after due to safety concerns.

Seven News aerial footage showed the car swerving across double lines and zigzagging around other vehicles.

A Victoria Police spokeswoman confirmed police were monitoring a vehicle detected driving erratically near Heathcote on Friday afternoon.

"The car was detected about 3pm in the Whittlesea area," she said.

"At this stage it is believed there are two people in the vehicle.

"We do not have any further information at this stage and will update when more information comes to hand."

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Seven News reported police could be heard over a scanner talking about the pursuit.

"So we've pounced on them. Unfortunately the car's fled the scene," the officer said.

"Two males on board. There's still a John and a Michael in the car."

The manager of the Coles Express in Kilmore confirmed the driver did not pay for petrol.

"I've got a police officer with me now, so I cannot say much," the servo station manager told Fairfax Media.

A witness in Kilmore, who gave her name as Julia, said she pulled into the Aldi carpark with her two children shortly before four cop cars blocked the entrance just before 4pm.

She says she saw two girls "giggling and running" into Aldi.

"Two cops ran into the Aldi and arrested them," she said.

"They probably weren't 16, but that's what they looked like."

The driver also stopped at the Shell Service in Lancefield but did not get any fuel.

A store attendant said he heard the driver put his brakes on, but by the time he went outside they were gone.

"I didn't even look at them because I was inside," he said.

"They didn't fill up anything."

Rose Taylor, an employee at Heathcote Winery on High Street, said she didn't see the car itself, but she did see "a lot of police flying by with their sirens".

"I had one customer in," she said.

"Being Heathcote, not much happens — we were both wondering what was going on."

Thousands of people watched live footage of the car speeding through Victoria on Channel 7 and Channel 9 on Facebook feeds earlier on Friday afternoon.

The two remaining occupants of the stolen car are known to police but still at large.