A man was trapped for an hour on a bus that was involved in a collision with a truck and a van in Melbourne's east on Tuesday.

He was one of four people injured when the truck hit the side of the SmartBus at the intersection of Foote Street and Williamsons Road in Templestowe about 11.50am.

The man in his 40s was trapped on the bus for about an hour before being taken by ambulance to the Royal Melbourne Hospital with a leg injury.

A man aged in his 60s, also on the bus, suffered minor injuries and was taken to the Austin hospital in a stable condition.

A female passenger was also injured and treated by paramedics, but was not taken to hospital.

The driver of the van, aged in his 60s, was taken to the Austin in a stable position.

Only a small number of people were on the bus at the time, an Ambulance Victoria spokesman said.

The northbound lanes of Foote Street remained closed to traffic.