Residents fear more sinkholes could emerge as authorities confirmed a possible “factor” behind a gaping hole in the ground that appeared on a suburban oval.

The sinkhole, several metres wide, was discovered at AJ Burkitt Oval in Heidelberg, in Melbourne’s northeast, on Tuesday.

It was close to where tunnel-boring machines are digging the $26 billion North East Link project.

No one was injured, though residents have said they are worried about the impact on nearby homes, with million-dollar properties just a few hundred metres away.

VIDA Roads, the Victorian government organisation behind the North East Link project, has acknowledged the machines likely contributed to the issue.

“We are actually confident that the tunnel boring machines have been a contributing factor, not necessarily caused the problem, but certainly a contributing factor,” chief executive Duncan Elliott said.

The sinkhole is located near the North East Link road tunnel, which began work in 2024 and is being constructed underneath Banyule Reserve.

Once completed, the 6.5 kilometre tunnels will run 45 metres underground.

The North East Link website shows its tunnel boring machines are operating close to where the sinkhole formed.

A sinkhole several metres wide opened up in Melbourne near where tunnelling is taking place. Photo: Facebook

Michelle Giovas, president of community group Friends of Banyule, told AAP she was shocked and disappointed by news of the sinkhole.

She is demanding answers about what caused the collapse and whether it is linked to the tunnel boring works.

“This happened on a public space and it’s pretty hazardous,” she says.

Giovas fears more sinkholes could emerge nearby.

An exclusion zone remains in place, with locals warned to stay away, despite many gathering outside the area to photograph the pit.

Sheldon and Emilia Williams have lived in the area for 50 years, and said they’ve never seen a sinkhole this large.

“Everyone is nervous. Is their home safe?,” Williams told reporters.

“It could have happened anywhere. This tunnel travels underneath roads, schools, you just don’t know. If you’re dealing with tunnels anything can happen.”

Local residents say they had seen surveyors from the project at the ground shortly before Christmas and over the past week.

A hole several metres wide opened up at a local oval close to where boring machines were digging. Photo: AAP

Multiple sporting clubs use the reserve, including the Banyule Cricket Club, whose president Brad Bowler initially thought the photos circulating on social media were fake.

He told reporters nearly a dozen local cricket teams train at the oval during the week, making it one of Melbourne’s largest clubs.

“It’s a busy part of the surrounds and to have this taken away from us will cause disruption at the club,” Bowler said.

“There’s nowhere for them, we’ll try and find grounds because we lost some from the North East Link development.”

A spokesperson for the project said it was aware the sinkhole had emerged near tunnelling operations.

Opposition Leader Jess Wilson urged the state government to be upfront with residents about the North East Link.

“What we see here, last night the scenes of local residents on a nice summer’s evening out at the park with their dogs and suddenly a sinkhole develops because of the mismanagement of the North East Link project,” she said.

Transport Infrastructure Minister Gabrielle Williams on Tuesday confirmed the tunnel-boring machines had stopped to allow space for an investigation into whether the sinkhole is linked to the project.

“Importantly, there’s no immediate risks to the community or residences in that area. The site has been secured,” she said.

In February 2025, construction for the project was halted after the discovery of a sinkhole near its Lower Plenty worksite.

‘Sinkholes happen’

Human activities including tunnelling could speed up the formation of holes and sinkholes, Melbourne University infrastructure engineering expert Guillermo Narsilio told AAP.

But sinkholes occurred everywhere and were relatively unreported internationally compared with Australia, Narsilio said.

“Sinkholes happen everywhere, but we tend to notice those in urban settings just because we are here to see them,” he said.

“As population grows and infrastructure ages, like leaking water pipes, together with changes in weather patterns and heavier rainfall, we are going to learn of more sinkhole appearances globally.”

A similar sinkhole opened up near former prime minister Malcolm Turnbull’s house in the well-heeled Sydney suburb of Point Piper in 2017.

No one was injured from the hole, which measured about 15 metres by 3 metres and about 2 metres deep, although four properties were evacuated.

A sinkhole opened up near Malcolm Turnbull’s house in Sydney’s east in 2017. Photo: AAP

University of Sydney geotechnical engineering expert Francois Guillard said sinkholes were underground holes that remained hidden until pressure became too much.

“When the cavity is large enough, the ceiling becomes too weak to be able to sustain the hole underground, and you have this sudden collapse of the ceiling of the cavity,” Dr Guillard told AAP.

“That’s usually when you see the sinkhole emerging at the surface, basically, and when you realise that there was a hole in the ground.”

Sinkholes are most commonly formed due to the dissolution of soluble rocks like limestone or dolomite, where water slowly dissolves them over a long period of time.

Much of Australia lacked widespread soluble rock near the surface, Prof Narsilio said.

More sinkholes could be seen in wet and tropical environments where more water was dissolved and in turn sped up rock dissolution and internal erosion, he said.

No one was injured when the sinkhole in Melbourne opened up.

It’s near the North East Link road tunnel, whose works began in 2024, and is being built under Banyule Reserve.

Once completed, the 6.5km tunnels will run 45 metres underground.

-AAP