Resident Jo Wynne told ABC Online that on Saturday her yard and house were covered in a black grit, which she believes came from the nearby coal loader.

She said several of her neighbours were also affected.

“It's just getting worse," she told the national broadcaster.

“We know we live in an industrial area but ... we shouldn't have to put up with all of this."

PWCS said its environmental officers have visited affected areas and are looking into the incident.

Meanwhile, PWCS general manager Graham Davidson said long coal ship queues off the coast of Newcastle are expected to continue for at least the next few months.

Scheduled track work and the commissioning of the Sandgate rail flyover caused the queue to lengthen in November, and delays are expected to remain until March.

“We see the vessel queue 14 days in advance and we're probably thinking that the demand for Hunter Valley coal will probably be sustained until the end of the first quarter," Davidson told ABC Online.