A Taiwanese ship carrying 49 crew has vanished in the remote South Atlantic Ocean without any sign of a mayday call but shortly after its skipper reported it was taking on water, authorities say.

The Hsiang Fu Chun, a 700-tonne squid fishing vessel, lost contact with its owners soon after reporting that water was leaking on to the deck at around 3:00am (local time) on February 26, officials said.

The vessel was sailing about 1,700 nautical miles (3,148 kilometres) off the Falkland Islands when it vanished, according to recorded satellite data.

Its crew include a Taiwanese skipper and chief engineer, as well as 11 Chinese, 21 Indonesian, 13 Filipino and two Vietnamese sailors.

Taiwan has launched a search effort, and is appealing for assistance from Argentina and Britain as well as other ships in the area.

"We still don't know where the ship is and what happened to it," Huang Hong-yen, spokesman for the local fisheries agency, said, adding that the government launched a search-and-rescue effort "immediately" after the ship's owners said it had lost contact.

He said there was no evidence the boat had sunk.

The ship was equipped with a system that automatically issues a mayday signal when placed under a certain water pressure, but no such signal was sent, he added.

The remoteness of the location was hindering search efforts, Mr Huang added, citing Argentine officials as saying it would take six days for a boat and 11 hours for a plane to fly to the area and back again, even in good weather.

Weather conditions in the area had been poor, he said, further hampering the search.

He said three Taiwanese fishing vessels operating there, including a sister ship of Hsiang Fu Chun, had been mobilised in the search.

"We'll do everything we can even though the search is like searching for a needle in the ocean," Mr Huang said.

He did not explain why it had taken authorities so many days to make the ship's disappearance public.

Some Taiwanese media speculated that the vessel could have lost power and be adrift, or could have been hijacked by crew.

But another official from the agency who asked not to be named said: "To be honest, the hope of finding the ship in that remote area is fading".

The South Atlantic Ocean is a traditional fishing ground for Taiwanese vessels, attracting up to 100 squid boats from the island each year.

The Taiwanese fishing fleet caught around 200,000 tonnes of squid last year, mostly for domestic consumption, according to the fisheries agency.

AFP