Nearly a week of constant crashing waves and a strong undertow has shifted sand but not caused erosion to the dunes and foreshore on Whangarei's east coast beaches.

The sand on beaches was already "steep" as a result of wind and surf conditions this winter.

Over the weekend, breaking surf was between three and five metres high, almost the size of that caused when Cyclone Pam's tail lashed Northland in March 2015.

Similar to during cyclonic events, the surf sets were breaking a long way out and becoming a fast-moving, churning wash of white closer to shore.

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While the beaches were hammered, there were no reports of dunes being eroded, large quantities of sand scoured away or other damage.

Yesterday the tide was still driving high but the height of the waves was beginning to ease. Whangarei District Council staff were to inspect vulnerable beaches such as Sandy Bay and Matapouri, parks and recreation manager Paul McDonald said.

In recent years Matapouri, where extensive dune-building was done 10 years ago, has been spared the erosion that undercut the sand and threatened beachfront properties. At Sandy Bay, high sand deposits had built up at the north end.

Mr McDonald said that despite the easterly weather and sand movement at several beaches, infrastructure risk remained "pretty low".

The sea was storming in through the entrance at Tutukaka mouth on Monday. Photo / John Stone
The sea was storming in through the entrance at Tutukaka mouth on Monday. Photo / John Stone

Northland Regional Council coast and rivers manager Bruce Howse said there had been some deep scouring at Waipu Cove a few weeks ago but no reports of further loss this week. The regional council is responsible for assessing coastal hazards and monitoring, while the district council does protection and remedial work.

The Tutukaka Marina was unscathed despite big waves through the narrow entrance and submerging the rocks.

Marina Management Trust chairman Terry Harris and staff said there was no damage to boats although "there was a lot movement".