A family of German tourists at the centre of a major rescue mission have been shown the best of Kiwi kindness after two of them were swept down the Pohangina River.

Ashhurst Constable Mark Glentworth said a man and his 11-year-old son were fishing down from Camp Rangi Woods, when he fell into the river and lost his shoes.

His son attempted to retrieve them and in the process, got caught in the current, but managed to get out of the river on the other side.

His father dived in to join him on the other side of the river, and they then separately tried to swim back across.

The 11-year-old was swept downstream in his attempt and his father dived in after him.

The man's wife, still onshore, went for help and emergency services were called about 9.30pm.

The man found his son clinging to some weed 2-3 kilometres downstream and together they scrambled ashore.

Almost five hours after emergency services were called, the pair managed to get to a house about 1km away at 2.15am to call off the alarm after battling their way uphill through thick scrub, facing livestock and braving an electric fence.

In the meantime, Search and Rescue, police, members of the Ashhurst Volunteer Fire Brigade, and other volunteers were out scouring the area for the pair.

The Palmerston North rescue helicopter was also called in, and went over the area with night vision goggles.

Mr Glentworth said the pair would have been scared and exhausted from their time in the water and their efforts across land in the dark, but appreciated the efforts made to help them.

The event was the second misfortune the family had faced since arriving in New Zealand earlier in the week. Shortly after landing in Auckland and loading their gear into a rental campervan, it was burgled.

All their belongings, including Christmas presents, were stolen.

Mr Glentworth said emergency response teams were extremely concerned and had been thinking the worst, so to find them both safe was a great outcome.

The local community had rallied to help with the search and staff from the Highland Home Christian Camp donated money, clothing and a present for the boy to the family after hearing about their ordeal.

Camp manager Melvyn Smith said the family had had "such a hard time" since arriving in New Zealand, and were incredible people.

He said they had told him the generosity they had been shown had "made their holiday".

- © Fairfax NZ News