UNITED NATIONS - The UN refugee agency said on Wednesday as many as 500 refugees and migrants may have lost their lives after an overcrowded boat sank in the Mediterranean Sea between Libya and Italy.

The incident, if confirmed, could be one of the worst tragedies involving refugees and migrants in the past 12 months.

The 41 survivors of the incident -- 37 men, three women and a three-year-old child -- were rescued by a merchant ship and taken to Kalamata, in the Peloponnese peninsula of Greece, on Saturday, the Office of the UN High Commissioner for Refugees (UNHCR) said in a press release.

The UNHCR team "has interviewed survivors of an overcrowded boat that sank in the Mediterranean in what could be one of the worst tragedies involving refugees and migrants in the last 12 months," UN spokesman Stephane Dujarric told reporters.

Those rescued include 23 Somalis, 11 Ethiopians, six Egyptians and a Sudanese, the spokesman said.

With summer approaching and the seas becoming calmer, this tragedy may be a harbinger of a deeper emerging crisis, reports said.

So far this year, around 25,000 refugees have reached the shores of Italy from North Africa, according to Italian authorities.

While those numbers are slightly more than the 24,000 who arrived during the same period last year, the United Nations and other refugee organizations are expecting more people to take rickety boats plying the risky routes across the Mediterranean to Italy.

The survivors told UNHCR staff that they had been part of a group of between 100 and 200 people who departed last week from a locality near Tobruk in Libya on a 30-metre-long boat.

"After several hours at sea, the smugglers in charge of the boat attempted to transfer the passengers to a larger ship carrying hundreds of people in terribly overcrowded conditions," UNHCR said in the statement. "At one point during the transfer, the larger boat capsized and sank."

So far this year, more than 179,000 refugees and migrants have reached Europe by sea across the Mediterranean and Aegean, and at least 761 have died or gone missing attempting the journey, Dujarric added.

The survivors include people who had not yet boarded the larger vessel, as well as some who managed to swim back to the smaller boat. They drifted at sea possibly for three days before being spotted and rescued, the agency said.

UNHCR visited the survivors at the local stadium of Kalamata, where they have been temporarily housed by local authorities while they were undergoing police procedures.

Meanwhile, the UN agency also reiterated a call for increased regular pathways for the admission of refugees and asylum-seekers to Europe, including resettlement and humanitarian admission programmes, family reunification, private sponsorship and student and work visas for refugees.

"These will all serve to reduce the demand for people smuggling and dangerous irregular sea journeys," the UNHCR said.

By the end of last year, refugees and migrants fleeing to Europe by sea have passed 1 million, according to figures released by the UNHCR, many on perilous trips aboard inadequate vessels run by people smugglers, with at least 3,735 more believed drowned.

In 2015, the UNHCR said 1,000,573 people had reached Europe across the Mediterranean, mainly to Greece and Italy, half a million of them Syrians escaping war in their country, with Afghans accounting for 20 percent and Iraqis for seven percent.