Two light planes collided on the runway at Melbourne's Moorabbin Airport in the city's south-east on Saturday, the Metropolitan Fire Brigade (MFB) said.

Ambulance Victoria confirmed three people were injured in the incident.

The three, including a man and a woman aged in their twenties, were taken to hospital with minor injuries.

Ambulance Victoria Spokesman John Mullen said two other people were treated at the airport grounds.

"All five people at the scene were treated for shock," he said.

There are reports the planes collided as one made an emergency landing.

Three people were taken to hospital with minor injuries after the plane crash. ( ABC News )

It is understood that plane issued a mayday call reporting engine troubles.

The second plane was taxiing on the runway when the collision occurred.

MFB Commander Paul Foster said both planes were severely damaged.

"I'm very surprised the people in the planes were not more badly hurt than what they actually are," he said.

"It was a very severe impact."

About 25 firefighters were called in to contain fuel leaking from both aircraft.

The Australia Transport Safety Bureau will investigate.