Families and relatives of the recent Greece migrant boat tragedy victims gathered at a camp near Athens as hundreds were still missing on Monday.

Inside the fenced migrant camp near the Greek capital, relatives hugged survivors while others refused to abandon hope of finding loved ones who were among the scores missing after one of the Mediterranean's deadliest shipping disasters last week.

Only 104 people are known to have survived when an aging fishing vessel carrying up to 750 people sank in the early hours of June 14 to the southwest of Greece.

There are 78 confirmed dead. Search and rescue operations are ongoing, although no survivors or bodies have been found since last week.

Relatives have been turning up outside the Malakasa migrant facility since survivors were brought here on Friday, showing photos of the missing through the camp gates, in the hopes someone might recognize them.

"I'm looking for my brother. I want to see where the boat sunk to try to find him," said 54-year-old Mohamed el Sayed el-Dadamony Radwan, who traveled from Germany, after reuniting with a nephew who survived.

Radwan showed a photo of his missing brother on his phone.

"I want to look for him because I can't find (his name), not in the hospital records of those who perished or in the list of those who survived," he said.

The vessel is thought to have set off with passengers from the Libyan coastal city of Tobruk on June 10. Most of them on board were from Egypt, Syria and Pakistan, Greek government officials have said.

Greek authorities say the vessel, which they had been monitoring for about 15 hours, flipped and capsized about 25 minutes after its engine stalled in the early hours of June 14.

They have said occupants of the vessel repeatedly refused offers of assistance, though international agencies, including Amnesty International, have called for greater clarity from Greece over the tragedy and whether enough was done to prevent it.

On Sunday, there was an emotional reunion for Syrian teenager Mohammad Hadhoud, 18, who survived the wreck, and his elder brother Fadi, who had first spotted each other through a metal barricade in the coastal city of Kalamata on Friday.

At Malakasa, Mohammad sprinted into his brother's open arms as they both sobbed, holding each other for several moments. Fadi said their brother-in-law died in the shipwreck.

Others had yet to receive news of loved ones.

"My uncle was with me on the same boat, the boat that capsized. I am looking for my uncle but I can't find him," said 22-year-old Egyptian survivor Atia Al Said.

Nine other Egyptians who survived are in Greek custody for questioning. They were taken before a magistrate on Monday.

In Pakistan, 14 people were arrested in connection with the alleged trafficking of several of the victims, police there said.