There are already reports of trees down in the Bay of Plenty as severe southwest gales blow through the region.

The MetService has issued a severe weather watch for strong winds.

The watch is also in place for Southland, Clutha, Dunedin, Southern Lakes, Central Otago, North Otago, Christchurch, Canterbury Plains, Nelson, Marlborough, Wellington, Wairarapa, Kapiti Horowhenua, Manawatu, Whanganui, Hawke's Bay and the Coromandel Peninsula.

'A series of fronts are forecast to cross New Zealand overnight Tuesday, preceded by strong northwest winds and followed by a very strong, cold southwest flow,” says the weather organisation.

'The strongest winds are expected about Wairarapa, Hawkes Bay south of Hastings, coastal Southland, Clutha, Dunedin, Banks Peninsula, the Port Hills of Christchurch and Nelson west of Riwaka and a warning remains in force for these areas.”

This watch is for the possibility of severe northwest gales in the following areas...

HAWKE'S BAY north of Hastings (not covered in the warning): From this evening until early Wednesday morning.

HOROWHENUA KAPITI COAST and coastal parts of MANAWATU and WHANGANUI: From this evening through to the early hours of Wednesday morning.

This watch is also for the possibility of severe southwest gales in the following areas...

COROMANDEL PENINSULA and BAY OF PLENTY, MAINLY NEAR THE KAIMAI RANGE: From Tuesday night to late Wednesday morning.

NORTH OTAGO: From Tuesday night to late Wednesday morning.

COASTAL CANTERBURY AND THE KAIKOURA COAST (not including BANKS PENINSULA and the PORT HILLS which are on WARNING): For a time Wednesday morning and afternoon.

COASTAL WAIRARAPA, ALSO THE WELLINGTON SOUTH COAST: From late Wednesday morning until Wednesday evening.

'Very large, potentially damaging seas are possible about some eastern and southern coasts, including the Wellington south coast.

'Also, brief heavy snow is expected above 500 metres for inland parts of Southland and Otago south of Cromwell until early Wednesday morning, which could affect many of the higher roads in these regions.”

The watch will be reviewed at 10am.