An estimated 170 people have died or went missing in two separate shipwrecks in the Mediterranean Sea, according to reports.

Some 53 people have died on the Alborán Sea, western Mediterranean, according to information from NGO sources, the UNHCR said in a statement.

One survivor is understood to have been rescued by a passing fishing boat after being stranded for more than 24 hours at sea and is receiving medical treatment in Morocco. Moroccan and Spanish rescue vessels have been searching for the boat and survivors for several days to no avail.

The Italian Navy are also reporting an additional shipwreck on the central Mediterranean. Three survivors were taken for treatment on Lampedusa, and reported that 117 people, who are currently dead or missing, were on board with them when they departed from Libya.

UNHCR said it has been unable to independently verify the death tolls for both shipwrecks.

“The tragedy of the Mediterranean cannot be allowed to continue,” said Filippo Grandi, UN High Commissioner for Refugees.

“We cannot turn a blind eye to the high numbers of people dying on Europe’s doorstep. No effort should be spared, or prevented, from saving lives in distress at sea.”

Migrants, part of a group of 49, disembark from one of Malta's AFM Protector-class coastal patrol boats on January 9, 2019 after being transfered from the Dutch-flagged rescue Vessel Sea Watch 3 to Haywharf in Valletta,Migrants, part of a group of 49, disembark from one of Malta's AFM Protector-class coastal patrol boats on January 9, 2019 after being transfered from the Dutch-flagged rescue Vessel Sea Watch 3 to Haywharf in Valletta,

In 2018, 2,262 people lost their lives attempting to reach Europe via the Mediterranean Sea.

Watch: ‘Please don’t leave us out at sea in the storm’

The UNHCR said it is concerned that actions by states are increasingly deterring NGOs from conducting search and rescue operations, and is calling for these to be lifted immediately.

"At the same time, greater efforts are needed to prevent refugees and migrants from taking these desperate journeys in the first place. More safe and legal pathways to access asylum in Europe are needed for those fleeing war and persecution so that no one feels they have no other choice than to put their lives in the hands of unscrupulous traffickers and smugglers."

Sea-Watch 'rescues 47 from drowning'

Meanwhile, on Saturday, the Sea-Watch 3 NGO vessel said it had saved 47 people from drowning, including eight unaccompanied minors.

On Friday evening, the reconnaissance aircraft Moonbird overheard communication about a distress case with a half-sunken boat and people in the water.

The Italy rescue centre refused to give Sea-Watch information about the case, claiming MRCC Tripoli to be responsible, which in turn was not able or willing to communicate, the NGO said.