Neighbouring landholders are concerned about food and pet food waste being dumped on a property at Whittingham.
The property "Narooma' that fronts the New England Highway was described in a recent sales campaign as being choice alluvial farming land with excellent water supply from The Doughboy and Mudies Creek, itself a tributary of the Hunter River, and located six kilometres from Singleton.
Locals have witnessed a unmarked semi-trailer with an unmarked tanker delivering the waste to the site.
One neighbour Wayne Cook, 'Castle Forbes' said the dumping of large quantities of waste products had been taking place all this year and the stench was becoming unbearable.
"The unmarked trucks arrive at dawn and unload their waste and disappear before anyone can see them," he said.
"The stench was so bad on the weekend we thought one of our cows had died but we realised as we approached the next-door farm it was coming from the waste."
Mr Cook along with other local farmers contacted the NSW Environment Protection Authority (EPA) over their concerns about waste being dumping on flood prone, alluvial flats that are bisected by Hunter River tributaries.
"That waste will wash into the Hunter River in any decent downpour," he said.
"My family have been on this property for 104 years and our livelihood as beef producers is at risk from someone who had been here 104 days.
"How can I now fill in the National Vendor Declaration for my livestock stating they have no access to human waste products - I have no idea whats happening next door and whats going into the soil and groundwater."
Mr Cook said the property was bought by Enviroking Waste Recycling Solutions a company based at Black Hill.
"I spoke to the owner of that company and he told me they would not be running livestock on the farm only carrying out rehabilitation of the land and the creeks," he said.
The NSW EPA said they are aware of residents' concerns and have confirmed that the material is food waste, which the EPA understands was supplied to the property owner for incorporation as soil enhancer.
"The owner is aware of the current odours being experienced and is required to undertake work, including covering the material to reduce the impact on neighbours," they said in a statement.
"A more detailed investigation into the food waste by the EPA is underway."
However on October 26 last year the EPA banned the use of mixed waste organics on farmlands and mine sites.
Mixed waste organic material/output (MWOO) is a composted product made predominately from organic material in household general waste - red lid bins.
Mark Ihlein, Singleton Council's Director Planning and Infrastructure Services said "Council staff were made aware of residents' concerns relating to the potential illegal dumping of materials at a property at Whittingham on Thursday.
"Staff then attended the site to investigate and became aware that the site is licensed by the EPA for the disposal and treatment of certain waste products.
"As a result, Council referred the complaints and investigation to the EPA as the regulatory authority and all further queries should be directed to the EPA."
Enviroking has been approach for a comment on this story and also Upper Hunter MP and parliamentary secretary for agriculture Michael Johnsen.
A public meeting regarding the issues surrounding the dumping of food waste will be held at the Whittingham Hall on Tuesday April 23 from 7:00pm.