Families sheltered on the second floor of their homes and others had to be moved by boat to higher ground as the Waikanae River burst its banks and swept through houses at Otaihanga north of Paraparaumu early today.

Paraparaumu Fire Service deputy chief fire officer Tim Morgan told NZPA they had been alerted around 3am today and along with three boats and a tractor from the Kapiti coast guard had helped some people move to higher ground to escape the floodwaters.

"Most of (the houses) were two-storey and a lot of them wanted to stay," he said.

"They stayed upstairs while the water ran underneath. There were a few people moved around to higher ground at the worst times but certainly nobody had to be evacuated out of the area."

Mr Morgan said the water had receded quickly after high tide at 6.30am.

"There's probably about five to eight houses where we're still waiting for the water to recede so we can assess the damage."

He said it was still raining but the worst of the rain appeared to be over.

Two fire engines were still on duty at the river and another was attending smaller floods at Pararaparaumu.

In Waikanae, about 700 people had to be evacuated to higher ground at the Waikanae Christian Holiday Park after the Waikanae River burst its banks.

Many evacuated campers from the holiday park, also known as El Rancho, were expected to return home today, Kapiti Coast District Council emergency manager Don McGuire said.

Mr McGuire said Otaihanga, where about 18 homes were flooded, was the worst hit area on the Kapiti Coast and had "copped it for the whole district".

He said a resident had told him it was the worst flooding seen there for 40 years.

Mr McGuire said the Otaki River was also running very high and had been close to serious flooding.

It was understood one home in Otaki was flooded and the occupants evacuated.

Around Horowhenua, fire fighters and Horowhenua District Council contractors were kept busy during the night as people called for help with surface flooding.

Council emergency management officer Andrea Baylis said Waikawa Beach had been isolated by a metre of water covering the road.

Levin fire brigade spokesman Colin Laurie said they had been called to three homes during the night because of flooding but it had not been bad enough to start evacuations.