Four kayakers, including two young girls, spent a cold night in rough weather in the bush after they got into trouble on a river near Tauranga.

Two men, believed to be in their early 40s, set off yesterday with their 9-year-old daughters on a trip down Omanawa River to Omanawa Falls, near Pyes Pa, about 10km south of Tauranga, off State Highway 29.

Sergeant Craig Madden, of Tauranga police, told NZPA the group had set off at 1.30pm yesterday to the falls, after being dropped off by a family member.

"They had intended to kayak to the falls but a local advised them they would be better to hike the 2km to the falls and launch their kayaks from there," Mr Madden said.

"But they got into trouble because it took them a lot longer to traverse the river and they ran out of daylight.

"They decided it would be best to stay the night there rather than try to trek out. The gorge is hugely dangerous, so they made the right decision to stay overnight."

The group returned to the kayaks this morning and continued kayaking through the gorge.

"They weren't prepared for an overnight trip at all. But they had wetsuits and life jackets on which would have increased their insulation through the night," Mr Madden said.

Search and rescue and the police started looking for them last night but a helicopter could not be launched due to bad weather.

The TrustPower Tect Rescue Helicopter was sent out at 10am today to search for the group, pilot Todd Dunham told NZPA.

"What started as a day trip yesterday had turned into a night out in wet conditions. They set off a few kilometres from where we located them today," Mr Dunham said.

"We got the two girls out but the two men paddled the final kilometre downstream in their kayaks to their destination."

None of the group needed hospital treatment.