Ms Washington said she and residents had already been disappointed with the park’s subdivision for the Men’s Shed.

“Council ought to be caring for the much-loved park, not treating it with contempt,” she said.

Diesel found at the Hunter River in December was traced back to Boomerang Park after Hazmat was called to clean up the spill.

The NSW Environmental Protection Authority working with Port Stephens Council later identified the council depot, adjoining the park, as the source.The council said it notified residents in the vicinity on December 23, as soon as the source was confirmed.

A sheen was again found at the Hunter River on January 2 after a pump – installed to manage the depot spill – failed from what the council said was an electrical overload.

Ms Washington said it wasn’t good enough.

“Port Stephens Council must explain to residents how a diesel leak was able to enter a public park and then the Hunter River before it was noticed,” she said.

“It's clear that there's been a failure of systems, a lack of care and lack of oversight in order for this pollution event to have occurred.”

Port Stephens Council’s group manager of facilities and services Greg Kable said his team had complied with every EPA order.

"Council acted immediately after being made aware of any issue on December 15 and has worked alongside the EPA in compliance with their requirements,” he said.

“We have engaged an independent environmental petro chemical consultant to assist with this process.”

One of the EPA orders was that council should notify residents.

“We conducted a letterbox drop on December 23, as soon as we identified the source of the leak, to residents in the immediate vicinity of the site,” Mr Kable said.

“Once the consultant's report is made available next week, council will continue its communications to the community.”