An Auckland ferry cruised through the SailGP course last week, and near several catamarans out on the water.

"Not even a flying F50 was stopping this ferry," SailGP said on its official Instagram account.

An Auckland Transport spokesperson says the Bayswater ferry's skipper was called through by the race marshal on Thursday during a SailGP practice session.

There's a 30s video of it. Apparently they were given the go ahead but I bet the skipper was a bit nervous as those boats approached at speed as a swarm.