The boss of an English port says at least 32 casualties have been brought ashore after a collision between an oil tanker and a cargo ship in the North Sea.

At least 32 casualties were brought ashore, but their condition was not immediately clear.

Martyn Boyers, chief executive of the Port of Grimsby East, said 13 casualties were brought in on a Windcat 33 vessel, followed by another 19 on a harbour pilot boat. He said some crew were still unaccounted for.

Britain’s Maritime and Coastguard Agency said several lifeboats and a coast guard rescue helicopter were dispatched to the scene in the North Sea on Monday, along with a coast guard plane and nearby vessels with firefighting capability.

The RNLI life boat agency said “there were reports that a number of people had abandoned the vessels following a collision and there were fires on both ships”.

Video footage aired by the BBC and apparently filmed from a nearby vessel showed thick black smoke pouring from both ships.

Boyers said he had been told there was “a massive fireball”.

“It’s too far out for us to see – about 10 miles (16 kilometres) – but we have seen the vessels bringing them in,” he said.

RNLI said three lifeboats were working on search and rescue at the scene alongside the coast guard.

The tanker, believed to be the US-flagged chemical and oil products carrier MV Stena Immaculate, was at anchor at the time, according to ship-tracking site Vessel Finder.

The cargo vessel, container ship Solong, was sailing from Grangemouth in Scotland to Rotterdam in the Netherlands.

Coastguards said the alarm was raised at 9.48am (8.48pm AEDT).

The site of the collision is off the coast of Hull, about 250 kilometres north of London.