Stephen Carruthers was walking along the Anchorage breakwater in August when he saw the Port Stephens Council back hoe on the beach.

As the operator cleared the stormwater outlet it unloaded the sand into the water.

"Numerous tonnes of sand was pushed into the bay by the machine when the logical thing would have been to have an excavator back up the beach - not into the bay," Mr Carruthers said.

The western end of the beach has accumulated more and more sand since the marina breakwater was built and it has clogged stormwater drains as a result.

This was anticipated in an environmental impact statement before the marina was built.

The shallows and their seagrass - seahorse habitat - were studied at length before The Anchorage marina was approved.

Mr Carruthers was furious when he said the marina only got the green light on the condition that The Anchorage undertake ongoing  work. 

Namely to shift sand from the western end of the beach back to the east.

"The work has never been carried out and now we see council using rate payer money to address the situation," Mr Carruthers said.

"When I saw the front-end loader the other day I thought this is the living end."

The work carried out on August 12 was part of the council's Critical Drainage List program. 

"The area has been identified as a location requiring regular inspection and maintenance of drainage assets, to ensure the protection of surrounding areas from stormwater when drainage outlets are blocked by sand as a result of natural processes," a spokesman for the council said.

The migration of sand from east to west along the beach is the focus of a separate plan.

"The Sandy Point/Conroy Park Foreshore Erosion and Drainage Management Plan was endorsed by Council in April 2016, formalising the organisation's commitment to investigating works required in the area and progressing priorities set within the plan," the spokesman said.

"An immediate priority was to further investigate sand nourishment in the area surrounding Conroy Park.

"The proposed works aim to provide a buffer to Conroy Park from wave attack without negatively affecting the recreational value of the beach or the marine environment as an ongoing management action."

In the meantime the council has placed sandbags along the foreshore to "provide a degree of protection" in the event of large swells.

"Council has implemented interim measures to help protect Conroy Park while the assessment and refinement of the proposed nourishment works continues," the spokesman said.

The August-incident will be the subject of an internal council review.

"Council will be investigating works undertaken on August 12 ensuring crews are maintaining best practice in all drain clearing activities," the spokesman said.

The Wests Group, which owns the the Anchorage Hotel, but not the marina, declined to comment.