From a luxury megayacht anchored at the Greek island of Kefalonia, Sinead McNamara made a distressing call home shortly before her death, her family's lawyer says.

Speaking to her mother and brother, the 20-year-old Instagram influencer was crying as she told her family about an incident that happened involving another member of the crew, the lawyer revealed.

The family's lawyer said Sinead McNamara cried in her last phone call to her family. Credit:Facebook

"The deceased had communicated by telephone with her mother and brother shortly before the unfortunate incident under investigation," lawyer Charalampos Triantafyllopoulos said in a statement.

"She was crying and referred to an incident that took place on the yacht with another crew member."