Machete-wielding thugs forced entry into a secure youth mental health hospital before assaulting two people and fleeing before police arrived.

Some staff from the Parkville Youth Mental Health and Wellbeing Service’s Sunshine hospital are now being relocated due to ongoing safety concerns, following Tuesday afternoon’s brazen attack.

Mental health workers, who asked not to be identified because of safety concerns, told this masthead that four people wearing balaclavas and surgical masks stormed into the ground floor reception area of the hospital about 3.45pm trying to locate an unnamed person.

A worker from one of several other organisations that share the Harvester Road building was assaulted by members of the group, including one member who yelled, “Who do you rep for?” during the brief attack.

A young person who was in the reception area at the time of the attack is also believed to have been injured by the group, who threw furniture and billiard balls during a short rampage.

A security guard who witnessed the attack from a first-floor balcony called police. After the balaclava-clad intruders were told that police were on their way, two of the members produced machetes, before the group fled about 3.50pm.

Police arrived about 4.15pm but could not locate the group. A police spokesperson confirmed they were investigating reports of the July 28 assault in Sunshine.

“Officers believe two men were assaulted by four males at a community centre on Hampshire Road about 3.50pm,” the police spokesperson said.

“The victims, both aged 19 from Melton and Wyndham Vale, were not physically injured. The offenders left the scene in a vehicle.

“The investigation remains ongoing. However, it appears as though the men are known to each other.”

Parkville Youth Mental Health and Wellbeing Service has been contacted for comment.

The organisation is relocating some of its Sunshine services to another location in the wake of the attack. A dozen other mental health, youth and community services occupying the Visy Cares Hub in Harvester Road are evaluating their response.

Parkville Youth Mental Health and Wellbeing Service (PYMHWS) operates a secure mental health service on the building’s first floor, though there is no public signage and its presence is not promoted to the public. The hospital shares the location with youth mental health support service headspace’s Sunshine service, run by Orygen.

Speaking via the Health and Community Services Union, so they could protect their identities due to safety concerns, an Orygen-headspace worker told this masthead that Tuesday’s attack was the latest in a series of recent incidents at the site.

“Morale in the last few months has been at an all-time low, particularly due to staff feeling unsafe,” one said. “After a few bad incidents a few months ago, all they’ve done is change the locks.”

The union’s Victorian branch secretary, Paul Healey, said Tuesday’s attack was deeply distressing for the mental health workforce from headspace, Parkville Youth Mental Health and Wellbeing Service and the consumers they cared for.

“We’ve welcomed the immediate actions of PYMHWS whose staff have opted to move off site until such time as the workplace is safe,” Healey said.

Anyone who witnessed the incident or with information or CCTV/dashcam footage is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report at www.crimestoppersvic.com.au