Contractors for the Port Macquarie-Hastings Council worked for more than seven hours to create a 135-metre long channel between Lake Cathie and the ocean.

The move came after the council voted this week to scrape the sand between the lake and the ocean at the northern end, known as the "berm", at a depth of 1.2 metres and a width of six.

"The berm is acting as a dam to the lake. If we scrape that down, the water will remain in the lake, which will protect whatever aquatic life may be in there," said mayor Peta Pinson.

"It will create a spillway over the top of it, the tides may move in over, and if we have some large seas it could break through, in which case the water will come out anyway — a channel will form itself."

Scraping follows recommendations

The decision by the council to scrape comes in response to recommendations made to it by the DPI Fisheries and National Parks.

PMHC mayor Cr Pinson said she pushed for a deeper channel to be excavated, but that was voted down.

She said the council was "just a small player" in the management of the lake.

"I did make a comment that what we're faced with is a lake that council has managed for many years which is basically unmanageable," she said.

"We're only responsible for flooding, which is happening at the moment.

"What may happen is that the ocean may take over and do the job itself.

"This has been a long fight for me. I have been on this matter for the past 12 months and I have realised that there's no amount of amendments [and] motions that you can put up to provide the community with want they want, when there are other factors at play."

Community group Revive Lake Cathie had been strong advocates of regular scraping for 12 months, said its president, Danielle Maltman.

"Some action is better than no action, particularly for our marine life and health and safety of our community and its people."