High tide's expected to put more pressure on infrastructure already-impacted by wet weather in the Upper South Island

A local State of Emergency's been declared for Nelson, Tasman and Marlborough, as heavy rain continues to fall.

MetService says an Orange heavy rain warning's in place until midday, while parts of State Highways 6, 60 and 63 remain closed.

Nelson Mayor Nick Smith says a number of local roads are also shut, due to surface flooding.

He says the city has had heavy rainfall this month, so the risk of land slips is being exacerbated.