A storm's barrelling towards the upper North Island - and could affect holiday weekend plans

The Fiji Metereological Service is saying the weather system may become a tropical cyclone by late today.

MetService says torrential downpours and gusts up to 140 kilometres an hour will begin in Northland overnight.

It's forecast to move on to Great Barrier, Auckland and Coromandel from late on Wednesday, and early Thursday.

Auckland Emergency Management General Manager Adam Maggs says people should be prepared.

He says essentially it's going to be messy, wet and windy in the days leading up to when people may want to travel for Easter.