Singapore | A 64-year-old Indian woman on board a cruise ship has gone missing as the ship sailed through the Strait of Singapore from Penang, the northern island state of Peninsular Malaysia.

The incident was reported on Monday with Reeta Sahani and her husband Jakesh Sahani on their way back to Singapore from Penang aboard the Spectrum of the Seas. Monday was also the last day of the couple's four-day cruise, reports said.

Jakesh, 70, woke up to find his wife missing from their room, according to a report by The Straits Times on Tuesday.

The retiree tried to locate his wife on the sprawling cruise ship but in vain. He later informed the ship's crew, who told him the ship's overboard detection systems had been alerted that something had fallen from the vessel into the Singapore Strait.

It is a 113-km long and 19-km wide busy shipping route between the Strait of Malacca and the South China Sea with Singapore on the north of the channel.

Jakesh's son, Apoorv Sahani, who was not on the cruise, said his family members are still in the dark about his mother's current status.

The 39-year-old architect said his mother could not swim, and that his father was made to go through an interview with the police that lasted a few hours.

“We have asked to see the CCTV footage, but, so far, we have not received anything yet for us to confirm that it was her. All we know is that the ship's crew thinks she jumped into the water,” the broadsheet quoted Apoorv as saying.

“Eventually my father was told to get down from the ship because there was another cruise that was going to take place, but we think she may still be on the ship, stuck somewhere,” he said.

Apoorv added, “She was on a holiday enjoying herself and then this whole thing happened. It does not make sense.” Meanwhile, the Maritime and Port Authority of Singapore (MPA) said in a statement on Monday that the Maritime Rescue Coordination Centre (MRCC) Singapore was notified about the incident at about 7.50 am.

The passenger was on board the Cyprus-flagged Spectrum of the Seas, and had fallen overboard, although no further details were provided, it said.

“MRCC Singapore is coordinating the search and immediately issued navigational safety broadcast to vessels in the Singapore Strait and vessels in port to keep a lookout for the missing person and report any sightings to MRCC Singapore,” said the statement.

It added that the vessel was berthed earlier in Singapore to support the investigations and had departed at around 4.30 pm.

Checks on marine tracking website Marine Traffic showed that it is currently bound for Nha Trang in Vietnam.

A spokesman for Royal Caribbean, which operates the vessel, said the incident was reported to local authorities immediately.

The company declined to comment further, citing the privacy of the guest and their family, but said its team is offering support and assistance to them.

According to cruise tracking website CruiseMapper, Spectrum of the Seas is the first Royal Caribbean cruise ship belonging to the Quantum-Ultra class – a larger and upgraded version of the Quantum-class.

It has 2,137 staterooms and can cater to 4,819 passengers, with 16 decks, 18 dining options, four swimming pools and 10 outdoor jacuzzis.