The world's second-largest cruise line, Royal Caribbean, will offer free cruises to firefighters as it redeploys a giant ship to Australian waters.

Spectrum of the Seas, a billion-dollar cruise giant capable of carrying up to 5622 passengers, will come to Sydney after the coronavirus saw it unable to cruise Asian waters.

The ship, which was purpose-built for the Chinese cruise market, has reportedly lain idle since the coronavirus hit.

It has been several weeks since the ship visited a Chinese port.

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ROYAL CARIBBEAN Spectrum of the Seas features a wave machine for surfing, an observation ball attached to a crane that raises 91 metres above the deck, a skydiving simulator and many other family attractions.

Details of the free cruises are yet to be fully released, but a spokesperson for Royal Caribbean said there would be two complimentary sailings on board the new ship.

"It is our privilege to offer two complimentary sailings on board our newest super liner Spectrum of the Seas from Sydney in the coming weeks, as a way of thanking the incredible first responder community who worked tirelessly over the bushfire season," the spokesperson said.

"We are in a fortunate position to offer such brave members of our community and their families the chance to join us for a few days to relax and unwind.

"We will be announcing further details in the coming week following consultation with the relevant authorities, including cruise schedules and the booking process."

Passengers on board Spectrum of the Seas can choose from 20 restaurants, including Jamie's Italian by Jamie Oliver. The ship also features a wave machine for surfing, an observation ball attached to a crane that raises 91 metres above the deck, a skydiving simulator and many other family attractions.

Royal Caribbean announced last week it had cancelled 18 cruises in south-east Asia.

Asia accounts for about 10 per cent of the global cruise industry, the Cruise Lines International Association says.

But the fear is that the negative headlines generated by the predicament of the Diamond Princess ship off Japan - the location of the most new coronavirus infections outside China - as well as by the two-week rejection of the MS Westerdam, which was turned away by five countries, will spill over to the entire industry.

"Cruise lines are scrambling as the situation unfolds, to cancel and move their floating resorts to safer destinations," cruise expert Stewart Chiron said.

Last week, Cunard cruise line's Queen Mary 2 offered incredible discounts on an Australian cruise after the ship was also redeployed from Asian waters. Passengers could book a 17-day cruise from Fremantle to Sydney for less than $1000. The cruise quickly sold out ahead of its departure.

Another Cunard ship, the Queen Elizabeth, called off stops in Hong Kong and Shanghai through April 4. Its revised itinerary has yet to be announced.

- Traveller