Close to 70 buildings across Auckland are being assessed for any impacts of flooding

The city was buffeted by a wave of thunderstorms and heavy showers around 7 this evening.

There've also been watches for Northland, Waikato, Waitomo and Taumarunui.

Mayor Wayne Brown says Auckland Emergency Management, partner agencies and contractors will continue to respond quickly to unfolding events.

The council's completed 16 rapid building assessments, and will be undertaking another 53 in the coming days.

In Northland, a slip on State Highway One over the Brynderwyns has blocked the southbound lane.

NZTA says caution is needed until the slip is cleared.

North Canterbury's under a heavy rain warning.

Warnings are also in force for Tasman and Taranaki Mounga.

Metservice says streams and rivers may rise rapidly, and driving conditions may be hazardous with ponding and slips.