A police hunt is continuing for two men who allegedly fled the scene of a fatal car crash as officers try to piece together the events leading up to the tragedy.

Two boys were killed after being thrown from a car which crashed on a suburban street in Ashcroft in Sydney’s southwest about 10.50am on Monday.

The boys are yet to be formally identified but are believed to be aged between 10 and 15.

Police are searching for a duo seen running from the scene and also want to speak to an unknown person caught on CCTV circling the wreckage on a trail bike almost immediately after the crash.

NSW Police Assistant Commissioner Brett McFadden described it as a “weakness of character” for the adults to flee the scene and urged the driver and passenger to contact police.

“We do know that for the four of them to be in the car, there’s an association there,” he said. 

“So if … they were friends and associates, and this tragedy has taken place, and they step away from their responsibility, it’s unacceptable.”

The crash happened on a street with a 50 km/h speed limit, but Mr McFadden said the car was travelling well above that and “separated in half quite dramatically” after smashing into a pole.

“The community should be outraged and the wider community should take stock that this is a direct result of speeding,” he said.

“The more we condone it and we engage in it, the more this is going to take place.”

The front half of the car ended up next to a jacaranda tree while the boot was strewn in the front yard of a home.

Wreckage from the crash also littered the road, with Mr McFadden describing the scene as one of “absolute destruction”.

Officers with police dogs scoured the bushland surrounding Cabramatta Creek at Magee Street and Maxwells Avenue in the hunt for the car’s other occupants.

Mr McFadden was also aware of a rider on a trail bicycle turning up at the scene immediately after the crash, and urged them to contact police. 

“We do not know what role if any he has played in the crash but it is certainly an active line of investigation that we are undertaking,” he said.