Cyclone Cody, which is tracking towards New Zealand, could bring large waves of up to eight metres.
In a statement, MetService said to expect settled weather for a couple of days before the tropical cyclone brings damaging waves, gale-force winds and heavy rain.
Cyclone Cody is due to impact New Zealand on Saturday afternoon, but MetService said 5-8m waves could hit from Friday onwards.
The forecaster said while it is unknown exactly where the greatest impact will be, areas including Coromandel, Bay of Plenty, Gisborne and Hawke's Bay look likely to bear the brunt of the storm.
Surf Live Saving New Zealand (SLSNZ) said in a statement the category one cyclone will bring dangerous conditions to Eastern beaches this weekend, with some popular beaches, including Mount Maunganui, forecasted to get huge waves by Sunday.
"Conditions created by the cyclone are likely to pose great risk to swimmers and people carrying out other coastal activities as they create strong rip currents, strong winds and large surging waves inundating the beach, which are a hazard for would-be swimmers and walkers alike,” SLSNZ national search and rescue Allan Mundy said.
Heavy swells building on the east coast of the North Island in the coming days are one of the earliest indicators that Cyclone Cody is heading our way, MetServices said.
"Though Cyclone Cody will no longer be a Tropical Cyclone by the time it affects New Zealand, this doesn’t mean it will have lost any of its sting," MetService meteorologist April Clark said in a statement.
"Currently, the exact path Cody will take over New Zealand during Sunday and Monday has significant variability, but it is clear that the upper two-thirds of the country will see some form of severe weather from the system and the north and east will get large swell.”
Metservice said people on holiday in unfamiliar parts of the country, especially near the east coast of the North Island, should find the MetService forecast for their current location.