Emergency services and harbour authorities braced themselves for a third round of damage from the spring equinox tidal action on Monday night.

The Zululand coast took a considerable pounding yesterday as Mother Nature unleashed her fury twice.

Richards Bay's beachfront took a hammering early on Monday as huge waves, driven by gale-force winds, scoured the beach and came within metres of crashing into the municipal beach office.

The beachfront and beaches around the harbour waterfront suffered further damage during Monday afternoon's phenomenal tide, which came close to causing major flood damage to the TuziGazi Waterfront.

Lifeguards evacuated the two-storey building and removed all valuables yesterday morning because municipal officials feared that although the structure rested on deep piles, erosion could make it unstable.

Tidal surges saw water flooding the changing rooms at Alkantstrand beachfront, leaving debris strewn across the picnic area.

Giant waves pounded the breakwaters at the entrance to the harbour throughout the day, damaging the south breakwater road and knocking down a brick lookout tower.

Richards Bay harbour has been closed since 6am on Sunday because of rough seas and gale force winds, which reportedly gusted up to 48 knots on Monday with swells of 6m to 10m.

The wind began dying down in the late afternoon, but there were concerns about Tuesday morning's high tide.

The passenger liner, Spirit of Adventure, which was to have docked in Richards Bay with 210 passengers on Monday, diverted to Maputo.

At St Lucia, the tide covered a large area of the main beach and flooded the estuary parking area.

The Greater St Lucia Wetland Park Authority said "significant" amounts of seawater continued to enter the lake system since the breaching of the mouth on March 2, which opened the lake to the ocean for the first time in five years.

Park CEO Andrew Zaloumis said the authority continued to be concerned about salinity levels and sediments entering the system.