A terrified father has spoken of how he locked himself in his bedroom after a gunman on the run held him hostage in his house in an hours-long siege.

The man, who was at home with only his one-year-old son, was trapped in the crossfire between the gunman and police for 2½ hours in Melbourne’s outer west on Tuesday.

Giving his name only as Ali, the father said he had no idea there was anyone in his house until he noticed his daughter’s bedroom door was locked. The man spoke to him through the door.

“He said ‘I have a gun’,” Ali told the ABC.

“It was horrible.”

The saga began when a 26-year-old man from Snake Valley, near Ballarat in central Victoria, allegedly carjacked a 70-year-old woman in the town about 2.30pm on Tuesday.

He led air police on a chase to Melton in Melbourne’s outer suburbs, where he got out and tried to carjack another vehicle.

The man was tracked to the neighbouring suburb of Weir Views, where he was confronted by officers out patrolling for him.

He allegedly fired a shot from a high-powered rifle at police but did not injure them.

The offender then allegedly broke into a house on Leon Drive where Ali was sleeping with his toddler son, trapping them inside for hours.

“I’m lucky. Anything can happen you know. The guy was with a gun,” he said.

“It’s unexplainable. If you’re not facing this sort of situation you won’t be able to understand. Imagine someone next to you with a gun.”

Ali called triple zero, and also spoke to his wife – who was not caught up in the siege because she had gone to pick up the couple’s other children from school.

Police negotiated with the gunman for hours before they could get Ali and his son out of the house. Photo: AAP

The Special Operations Group and the critical incident response team negotiated with the offender while communicating with Ali throughout the siege, Victoria Police Superintendent Michael Cruse said.

“Throughout the negotiations, we attempted for him to surrender and put the firearm down,” he said on Wednesday.

“We provided safe passage for that to occur. That did not occur prior to the incident unfolding.”

Officers were able to negotiate for Ali to leave the house through a front window just after 6pm.

During the siege, another shot was fired inside the home, leading police to enter. It is alleged the man then fired a shot at officers, and they returned fire.

“[Officers] were able to deploy a police dog, and the male offender was taken down and arrested,” Cruse said.

“It’s extremely lucky [that no officers were injured], and the offending is very serious, and it’s completely unacceptable that police members were exposed to this kind of danger.”

Asked about reports the man was in the backyard jumping on a trampoline before police intervened, Cruse said he had at times behaved erratically.

The man remains at the Royal Melbourne Hospital after being treated for a dog bite.

Police were expecting him to be discharged on Wednesday afternoon, when he will be interviewed and charged.

Police were also supporting Ali and his family.

“Investigators will make sure they get referrals and they’re OK, but undoubtedly, it is a terrifying incident – very, very traumatic – and we’ll need to support them through this,” Cruse said.

The man will potentially face a number of charges including aggravated carjacking, attempted aggravated carjacking, aggravated burglary, conduct endangering life, and firearms offences.

Ali has thanked his rescuers.

“They saved myself and my kid. I’m really glad the way they saved me,” he said.

-with AAP