UK foreign minister Liz Truss on Sunday announced her bid to succeed Boris Johnson as prime minister and leader of the ruling Conservative party.

"I am putting myself forward because I can lead, deliver and make the tough decisions. I have a clear vision of where we need to be, and the experience and resolve to get us there," she said in the Daily Telegraph newspaper.

Johnson this week announced he would resign after the mishandling of a scandal prompted a raft of ministerial resignations, firing the starting gun on a fractious race to replace him.

Truss, 46, is seen as one of the favourites in the Tory leadership race.

The number of candidates grew to 11 shortly after her announcement as MP Rehman Chishti followed suit with his own candidacy.