Luxury line Silversea are in the final stages of planning one of the most ambitious expeditions in the world – simultaneous multiweek cruises in both the Canadian and Russian arctics.

The voyage which combines the Northwest Passage and Northeast Passage is scheduled for the 2020 northern hemisphere summer, according to Mark Conroy, the managing director of the Americas for Silversea.

If the cruise goes ahead, Mr Conroy said that the cruise will start on August 10, 2019 in Nome, Alaska and venture east, north of Russia to the final port of Tromso in Norway.

The 25-day voyage is priced from US$37,170 aboard the Silversea Explorer and the cruise is almost booked out.

But Mr Conroy told Travel Weekly that the line is still investigating and evaluating whether it can safely accomplish both cruises and a final decision is expecting in the coming months.

The only other non-Russian cruise line, Hapag-Lloyd attempted the Northeast Passage. The line made the journey in 2014 as well as 2016 and took 23 days to complete. And the cruise line said it was one of the most inspiring journeys ever – it was said that the captain spotted 86 polar bears over the course of the 2016 cruise.

Mr Conroy said one of the greatest challenges of organising the cruise is that the Northeast Passage cruise cannot be insured which means that if the cruise is aborted because of factors like ice clogging the routes, guests won’t get full refunds.

The ship would be accompanied by an ice breaker if the ship gets stuck.

Silversea has been at the forefront of developing the luxury expedition cruise sector – the line has acquired two more expedition vessels and next year, is converting its oldest ship, the Silver Cloud into an expedition vessel.