Police say a truck driver who sparked a major incident on the Monash Freeway in Melbourne this morning had a suspicious device strapped to his head as he drove at 100 kilometres per hour on the wrong side of the road.

The busy road was locked down for three hours as police evacuated the area and called in the bomb squad which confirmed the device was not a bomb.

The 35-year-old driver remains in hospital undergoing psychiatric evaluation.

The incident began at about 4:00am (AEST) after a motorist reported a broken down prime mover on the freeway near Toorak Road at Glen Iris.

When police arrived and approached the driver they found he had what appeared to be a suspicious device strapped to his head.

Sorry, this video has expired Truck driver had 'suspicious device' strapped to him

The man refused to cooperate with police and drove off at speeds of up to 100 kilometres per hour into oncoming traffic.

"The police were able to quickly evacuate all the people that were at the Toorak Road intersection and move them right back out of the danger from this truck," Detective Acting Senior Sergeant Martin Bourke said.

"Fortunately for us he managed to stop the vehicle just short of the civilian's vehicles."

Detective Acting Senior Sergeant Bourke said the man was talking to police but he was not making any sense.

"He appeared to have some form of mental condition that was affecting his ability to speak with us," he said.

"After 10 minutes of negotiation he got out of the vehicle. He took his clothes off of his own free accord.

"He removed the device and walked towards police where he did exactly what he was told and surrendered."

The man, from Caulfield South, has been taken to the Alfred Hospital for evaluation and is expected to be charged after being interviewed by police.

The freeway was closed for about three hours in the morning peak.

ABC cameraman Roy Frattinger was caught up in the incident on the way to work when traffic on the Monash came to a sudden stop just past Toorak Road.

"It was a parking lot basically, so I just pulled up in the group and the police came up and said they're shutting it down, you're not moving anywhere," he said.

"We all sort of piled out of the car and waited for a while, and they moved us back another 100 metres and it was then that they mentioned something about a bomb."

Frattinger said most people remained calm.

"If you'd been around closer to the area you might have been a bit more nervous about it," he said.

"Everyone was really calm. There was a woman with a kid of eight or nine [and] she was reassuring him.

"But that was basically it for stress really, most people wanted to get the heck off the highway."

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