In another sign of how big the battle for cruise passengers is going to be this season, P&O Cruises has announced it will be giving its guests a chance to win $1 million each to celebrate passing its four millionth passenger milestone.

The line will also be giving away $4 million in onboard credits for new bookings over the coming weeks.

From this week, the line will give four passengers the chance to win $1 million when they book a P&O cruise before November 25, the day of the Five Ship Spectacular on Sydney Harbour to officially launch the line’s new fleet.

Travellers will receive an onboard credit of up to $800* per room with their booking and also go into the draw for a chance to win one of four places on a P&O cruise to Moreton Island, sailing from Sydney on December 9, 2015.

There will be an astonishing “play-off” in which the four finalists will play a game in front of other guests.

For more information, click here.