The Transport Accident Investigation Committee's launched a marine safety inquiry, into a tourist boat running aground in Doubtful Sound

Fiordland Navigator's captain made a mayday call last night - after the vessel grounded with more than 60 people on board.

Passengers were taken to Te Anau, and the vessel re-floated later in the evening.

Investigators will start gathering evidence and interviewing witnesses this week.

Inquiries usually take two years.