Surf's up! MetService issues warning for rips and unusual currents as powerful waves expected to hit New Zealand coastline tomorrow

Powerful long-period swells set to hit the country's cost tomorrow has led to warnings from the MetService.

The MetService says although these waves will not be unusually high, the long period means that they will carry more energy than usual.

The event could lead to unusual rips and currents, and the MetService warns people unfamiliar with the ocean to stay out of the water.

However, for those with the necessary experience to safely assess the situation before venturing out, it will also mean some good surfing according to the MetService.

The period of these waves will be around 15 seconds by midnight tomorrow, and although the size will only be around two metres for the North Island and three metres for the South Island, they will pack a bit more punch than usual.

Click here for more forecasts of the wind and waves from MetService.