At least six people were killed late Saturday in the Mediterranean Sea off the northern port city of Tripoli in the country's deadliest such maritime incident in years.

The circumstances were not entirely clear, with some on board claiming the navy rammed their boat, while officials have insisted the smugglers attempted reckless escape manoeuvres.

The government in an emergency session "tasked army command with conducting a transparent investigation into the circumstances behind the incident under the supervision of the relevant judicial authority," said Information Minister Ziad Makari.

The announcement came after survivors took to TV stations and social media to accuse the military of insulting passengers aboard the vessel and then deliberately cracking its hull.

The disaster ignited widespread public anger just weeks before May 15 parliamentary elections in the small country hit by a severe economic crisis in recent years.

The Lebanese armed forces said 48 people were rescued, but it has remained unclear exactly how many would-be asylum seekers were crammed onto the boat when it set off.

The United Nations refugee agency UNHCR said the boat was carrying at least 84 people when it capsized about three nautical miles (3.5 miles, 5.5 kilometres) off the coast.

Families have reported at least 23 still missing, all women and children, according to Tripoli port director Ahmad Tamer.

They include seven Syrians and two Palestinians, Tamer said.

Lebanon was once a transit point for asylum seekers from elsewhere in the Middle East who were hoping to reach the European Union island state of Cyprus, 175 kilometres (110 miles) away.

However, Lebanon's unprecedented economic crisis that has plunged millions into poverty is driving growing numbers of its citizens to also attempt the perilous crossing.

The UN says more than 1,500 people have tried to leave Lebanon illegally by sea since the start of 2021.