The bodies of at least 74 African migrants have washed ashore in western Libya, humanitarian officials said, in the latest tragedy at sea along a perilous trafficking route to Europe.

The bodies were found near the city of Zawiya on Monday, Libyan Red Crescent spokesman Mohammed al-Misrati said, adding that he feared more might surface.

He said a torn rubber boat, the kind that usually carries up to 120 people, was found nearby.

The Red Crescent's branch in Zawiya said there are bodies still floating out at sea but it has no means to retrieve them.

The International Organisation of Migration said traffickers took the engine and left the boat to drift.

Twelve migrants remain missing and are presumed drowned, and a sole survivor was taken to hospital in a coma, the UN agency said.

The Red Crescent posted photographs of dozens of bodies in black and white bags, lined up along the shore.

Mr al-Misrati said the bodies would be taken to a cemetery for unidentified people in the capital Tripoli. The Red Crescent appealed for help on Facebook, saying there are no vehicles to transport the bodies.

Libyan coastguard spokesman Ayoub Gassim said more than 500 migrants were rescued at sea on Friday and Saturday off the coast of Sebratha, a city west of Zawiya. The migrants' boats were about five to seven miles from the coast.

Mr Gassim said the smugglers pack larger rubber boats with up to 180 people, dramatically increasing the risk of capsizing.

"We are seeing the new boats, which are not equipped with anything, but they carry more people. This is going to be even more disastrous for the migrants."

The Libya to Italy smuggling route across the Mediterranean saw record numbers of migrant drownings last year, Fabrice Leggeri, director of the European Border and Coast Guard Agency, said last week.

Some 4,579 migrant deaths were documented, up from 2,869 the previous year and 3,161 in 2014. The real number is believed to be much higher.

Mr Leggeri blamed the small dinghies and poor vessels used by the smugglers for the high death rate. The smugglers also appear more willing to brave the choppy winter sea.

January alone saw 228 recorded deaths, by far the biggest monthly toll in recent years. The IOM said the latest tragedy brings the total this year to 365.

More than 180,000 people made the crossing last year, an increase of 17% from 2015.

Libya was plunged into turmoil by the 2011 uprising that toppled and killed long-time dictator Muammar Gaddafi, and has since emerged as a popular, if extremely dangerous, route to Europe for those fleeing poverty and civil war in Africa.

Libya is largely governed by local militias, many of which profit from the trafficking. Rights groups say migrants traversing Libya have been tortured, raped and subjected to forced labour.

The European Union has plans to halt the tide by training the Libyan coastguard and stepping up co-operation with neighbouring Algeria, Tunisia and Egypt, but rights groups fear such measures could leave tens of thousands of migrants stranded in the country.