Dozens of sharks have been spotted closer to shore than usual in Wellington's Oriental Bay.

Photo: Sean Gillespie / @OrientalBayNZ

The rig sharks were spotted yesterday and can grow up to 1.5 metres long.

NIWA principal scientist Dr Malcolm Francis said the sharks come in every year in spring and summer.

"The females come into bred, they give birth to live young, and the males come in and the male and females mate after the females give birth, he said.

Dr Francis said what's surprising this year is how close to shore they're coming.

However he added the sharks are harmless.

"They have very blunt paving stone like teeth which they use for crushing up hard shell crabs and molluscs, so even if they did bite they don't have sharp teeth that can do any damage with."

He said they often feed on crabs and worms in muddy areas and if they're more abundant this year, that may be why they're coming into shallower waters.

The Department of Conservation is advising the public to give the sharks their space.

"Please don't approach closer than 20m, touch or chase them. When animals get scared they can become aggressive to protect themselves," they said.