After departing Brisbane on Sunday for a seven-day Pacific voyage, Carnival Luminosa returned to avoid a tropical cyclone in the Coral Sea. On Wednesday morning, passengers were informed that they are on their way back to Australia instead of visiting Lifa in New Caledonia.

In a letter to guests the ship Captain Carmelo Marino said, “Unfortunately, given the forecast track of the storm, we will not be able to deliver our planned South Pacific itinerary.

"We will enjoy a few days at sea as we head back to Brisbane," Marino wrote.

"Meanwhile, our team is trying to secure a visit to Moreton Island for Friday (weather permitting)."

A $200 room credit and half-price tickets on a future cruise were offered to passengers.

Carnival Australia spokesperson said the safety of passengers and crew was the company's main priority. Other cruises from Brisbane were forced to change their route and itinerary. Royal Caribbean Quantum of the Seas, which left Brisbane on Tuesday, is sailing to Tasmania instead of the South Pacific.

The Bureau of Meteorology predicted that tropical cyclone Gabriel, which was a Category 1 early on Wednesday afternoon and is located about 730 kilometers northeast of Mackay, could reach Category 3 by Thursday.

"Tropical Cyclone Gabrielle has developed over the northern Coral Sea," the bureau said.

"Gabriel is forecast to continue to track south for the rest of Wednesday and then southeast from Thursday, staying well off the Queensland east coast."

"It is expected to strengthen further on Thursday and Friday, becoming a severe tropical cyclone."

The system is expected to move southwest across the Coral Sea and affect Norfolk Island over the weekend, bringing heavy rain, strong winds and possibly dangerous and damaging surf.

The system has sustained winds of 75 kilometers near the center, with gusts up to 100 km/h.