A baby boy is fighting for life in a New Zealand hospital after being thrown from a van in a holiday crash that injured eight people.

Police say it was good luck no one was killed when the van plunged down a 10-metre bank on a remote stretch of State Highway 5 between Napier and Taupo on Thursday morning.

The baby and a man in his 30s are in critical conditions in Hawke’s Bay Hospital’s intensive care unit.

The six-month-old boy is from Melbourne, Radio New Zealand reports.

Five passengers from Australia were travelling from Auckland to Hawke’s Bay with three New Zealand family members, the broadcaster said.

A man carrying the boy escaped from the van, which landed on its roof and was partially crushed, and climbed up the bank to wave down passing motorists.

The remaining six people, including three men, one woman and two girls, had to be rescued and winched up the bank before they were taken to hospital.

Three men, one in his 20s, one in his 30s and one in his 40s, a woman in her 30s and a nine-year-old girl are all in stable conditions in hospital.

The road was closed for five hours while emergency services dealt with the crash, and three rescue helicopters were involved.