AN alleged Sydney drug dealer transporting more than $200m of ice has come unstuck after he crashed into a parked police car in front of a Sydney police station.

Police said the 28-year-old was driving a Toyota Hi-ace van when he ran up the back of a police car in front of Eastwood police station at 10:30am on Monday.

Soon after an inspector from a neighbouring police command pulled over a van in Church Street Ryde and after speaking to the driver searched the van.

After moving some boxes in the back and opening them he allegedly found a substance police believe to be crystal meth.

The man allegedly told police he was just transporting food around the city.

"Presumptive testing returned a positive indicator for methamphetamine," a police spokesman said.

"In total, police seized 273kg of ice, which has an estimated potential street value of more than $200 million."

The 28-year-old driver from Berala was arrested and taken to Ryde police station where he was charged with large commercial drug supply, negligent driving, and not give particulars to police.

He is due in Burwood Local Court on Tuesday.

Detectives from the Drug and Firearms Squad are now also helping with the investigation.

Police are asking motorists who may have dashcam footage of the van anywhere in the Ryde-Eastwood area on Monday to contact Crime Stoppers on 1800 333 000