The South Island and lower North Island are to be blasted by wind and rain over the next couple of days.

The MetService is warning of a "significant storm" starting tomorrow, when an intense low is expected to move onto the South Island Tuesday afternoon and evening.

An associated cold front will also move north over the North Island.

"This significant storm is expected to bring heavy rain to parts of the South Island, and widespread northwesterly gales to the South Island and the lower parts of the North Island," MetService said on Monday.

The heavy rain is expected in Westland, Fiordland and the headwaters of Canterbury and Otago rivers and lakes.

The winds are expected to be strong around South Taranaki, Whanganui, Manawatu, Kapiti-Horowhenua, Wellington, the Wairarapa south of Masterton.

Northwesterlies are expected to rise to gale during Tuesday evening and gust up to 140 km/h in exposed places.

Marlborough, Christchurch, Canterbury Plains and Canterbury High Country can also expect winds gusting up to 130km/h in exposed places.