Two people are injured, one of them critically, after a slip on Cape Kidnappers in Hawke's Bay.

Police, four fire trucks, a St John ambulance and a rescue helicopter were attempting to gain access to the scene off Clifton Rd about 3.15pm.

A large amount of earth and rock fell onto the beach at about 2.30pm on Wednesday.

One person has critical injuries and another has moderate injuries.

Both of the injured are being transported to Hawke's Bay Hospital, one by rescue helicopter and the lesser injured of the two by ambulance.

Video from Clifton Beach showed the slip falling into the sea on the northern side of Cape Kidnappers.

A man who was on the popular Cape Kidnappers Gannet Tour said the slip had occurred in two waves.

The group were on their way to the Cape when the first slip came down, he said. Half of the tour turned back and half, roughly 70 people, decided to press on before a second slip came down, the man said.

Police had told him all of the people on the tour were accounted for, he said.

Cape Kidnappers is a craggy but stunning peninsula. It is a popular tourist attraction with regular overland tractor rides along the beach at low tide to the gannet colony.

People can also walk the 8 kilometres along the coast from Clifton to the Cape. The slip is on this walking trail.