One man, believed to be in his 30s, was taken to Dandenong Hospital for observation but was not seriously injured, according to an Ambulance Victoria spokeswoman.
The freeway has been closed from Ferntree Gully Road, and police are guiding motorists stuck beyond this point to turn around and drive back up the emergency lanes – the wrong way up the freeway.
“Police are guiding them back up so they can get off at the exit behind them,” Mr Miller said. “It’s a very rare occurrence.”
Motorists are being urged to exit the freeway as soon as possible, with all backed up traffic now being diverted onto Springvale Road.
Mr Miller said all Melbourne motorists should avoid the Monash entirely.
“If you’re coming in on the Westgate don’t even go through the Burnley Tunnel – get off at Kings Way,” he said.
The Department of Transport advises drivers can also exit at Warrigal Road or Blackburn Road to head south to the Princes Highway.
Mr Miller said he expects all outbound lanes to be closed for at least a few hours until emergency services and tow trucks can remedy the scene.
While all inbound lanes of the Monash are open, traffic has slowed substantially.
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