Chief executive Rob Forlong said that had been the situation for 15 years, and the council only mowed berms in front of parks and other council-owned properties.
"Sharing the task this way keeps the district looking tidy and helps to keep rates down," Mr Forlong said.
"We have considerable sympathy for Mrs Edmunds and her neighbour, and [the] council's lawn-mowing contractor has offered to mow the berm outside their properties in a private capacity at very reasonable rates."
According to the Ombudsman, neither party is strictly responsible for mowing berms, said Whangarei man Colin Edwards who is acting in an advocacy role for the neighbours.
He said when the land was subdivided in 1999 the council compulsorily acquired and set aside the contentious area for road reserve as a safety measure for traffic rounding the wide curve.
"The meanest thing is that there were 22 sections in that subdivision but only those two have been lumbered with the job of mowing a huge area the council itself acquired specifically for road safety reasons.
"Council denies they mow other similar areas, but this is not true. They mow at least two others at Pah Rd, Onerahi, and Mt Pleasant Rd, Otaika."
Mr Edwards said it is frustrating to see council contractors taking ride-on mowers past the Whangarei Heads Rd corner to cut a large area of grass on the foreshore on the opposite side of the road.