Heavily armed tactical police have stormed a pub in Melbourne where a siege is taking place, five hours after two men barricaded themselves inside.

Officers were first called to Westmeadows Tavern in the city's north at about 5am after receiving reports of a burglary in process.

Two armed men have been holed up inside since, sparking a major police operation involving members of the Special Operations Group, Critical Incident Response team and the dog squad.

Just after 10am, some 15 officers stormed the pub with guns drawn after failing to negotiate with the pair. They are yet to emerge.

Police had earlier been using a loudspeaker to ask the men to answer the tavern's telephone so they could negotiate.

"Come out without anything in your hands," an officer could be heard saying.

Just after 9am - four hours on from the initial reports of a burglary in progress, more tactical officers arrived at the scene to assist. There were two armoured vehicles and dozens of police surrounding the pub, with two helicopters circling above.

Paramedics were also on standby.

The area was cordoned off. There was no one inside the building when the men broke in.

The pub is in proximity to a daycare centre and live footage from the scene earlier showed shocked parents being ushered away as they arrived to drop off their children.

"We ask that members of the public avoid the area," police said.

The Herald Sun reports that the venue has been targeted by burglars a number of times in recent years.

Bruce Allan, a local who lives nearby, told the newspaper that he was shocked to wake to find police swarming the area.

"Initially, I thought it was a car accident or something but then I got told it was a siege in the pub. It's pretty scary," he said.
"My son used to work there up until a few months back. It was robbed twice while he was there. Its happened probably four or five times over the past few years. It's usually the bottle shop but I don't know what it is this time."

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