A man who appeared to have a bomb strapped to his head led police on a chase down a Melbourne motorway before stripping naked and surrendering.
Police who were responding to a breakdown call were confronted by the man with a bomb-like device strapped to his head.
The 35-year-old man was arrested after a short police chase and a siege ended with him stripping naked and surrendering, police say.
About 50 police officers, including the bomb squad, responded to the incident near St Kevin's College that shut down part of the freeway and forced motorists to evacuate in the early hours of this morning.
Officers received a call to attend the truck breakdown on the Monash Freeway about 4am.
Detective Acting Senior Sergeant Martin Bourke said when police approached the driver they saw what may have been a bomb strapped to his head.
"Police then observed what appeared to be a suspicious device strapped to this male so we backed right off and tried to negotiate with the male,'' Det Bourke said.
"The device was around his head.''
After negotiation attempts failed, the man drove his truck away from police. They chased the driver for about 4km before he stopped, did a U-turn and started driving into on-coming traffic on the Monash Freeway.
Police stopped the traffic at Toorak Road and evacuated the freeway.
"In his truck, in his prime mover he got up to about 100km/h, accelerating quite quickly towards the oncoming traffic,'' Det Bourke said.
"It was an incredibly risky situation.''
The man stopped his truck just short of vehicles that had been parked on the freeway after their drivers were evacuated. Police again attempted to negotiate with the man, who stripped naked and then surrendered.
The man was arrested and taken to the Alfred hospital for a psychiatric evaluation.
Roads were re-opened about 7am after the area was declared safe. The device was not an explosive device.
The man didn't make any threats, Det Bourke said.
"He spoke to police quite a bit but they couldn't understand him,'' Det Bourke said. "He appeared to have some sort of mental condition.''
The man has not been charged.