NSW Environment Protection Authority (EPA) has released more details about what Gunnedah Shire Council will have to do after staff were found to be taking waste to Wandobah Reserve without permission.

In a statement released on Wednesday, the EPA said the council would have to pay almost $20,000 to Gunnedah Urban Landcare Group (GULG) to do the work.

Another $5000 can be used by the volunteer group "at its discretion" and the council will also have to pay $3000 to the EPA for its legal costs.

Read also:

The council voluntarily entered an enforceable undertaking with the EPA for the breach, which occurred on crown land adjacent to Alford Road.

GULG's Wandobah Reserve Activation Project will include planting 150 native tree seedlings in the reserve, inserting tree guards and stakes, and care and maintenance of seedlings.

More nest boxes will also be installed to promote native bird/mammal nesting, and cameras will be put in to deter dumping.

The council's offences occurred between February 2016 and March 2017.

It was brought to the EPA's attention in August 2016 by Fire and Rescue NSW after crew members were called to the reserve for a green waste fire.

EPA north director Adam Gilligan said when EPA officers inspected the site, they determined it was being used as "a waste facility" because they found "the land was being used to dispose of green waste and excavated material from water and sewer works, and that road sealing materials were being stored incorrectly".

Mr Gilligan said the council had expressed regret over the incident and taken responsibility for it.

"The council has taken appropriate measures since the investigation commenced to amend its procedures and clean up the site, and in this instance, the EPA considers the enforceable undertaking as the appropriate regulatory response," he said.