AN UNPLEASANT pong the NSW Environment Protection Authority (EPA) has identified as a 'rotten egg gas' type odour continues to hang around like a bad smell.
The stinky situation has wafted across a number of Newcastle suburbs, recently reported at Lambton, New Lambton, Broadmeadow, Islington, Hexham, Mayfield and Merewether.
The EPA confirmed it has received one complaint about the odour around Newcastle and has recently inspected the site.
An EPA spokesman said it suspects the odour is coming from decaying vegetation and stagnant water in wetlands and low-lying areas as a result of recent rainfall.
"Winter atmospheric conditions can commonly trap the odours close to the ground," he said.
"We understand that odours can be unpleasant for the community, and we will continue to monitor the situation in the river.
"There are currently no indications of fish deaths or a blackwater event."
A blackwater event is when a naturally occurring gas emanates from stagnant water in low-lying wetlands, often after heavy rain.
The EPA spokesman said officers have tested dissolved oxygen levels in the Hunter River from Hexham to Raymond Terrace.
He said those results showed the river was within normal ranges expected of estuarine river systems.
The 'rotten egg' odour was first reported earlier this month after an extended period of heavy rainfall hit the region.
At that time the smell had been reported in Wallsend, Adamstown and Waratah.
Hunter Water has confirmed the smell is not caused by or impacting on its operations.