An Italian family's Christmas celebrations turned into a nightmare after a mother and daughter died following a festive dinner.

Antonella Di Ielsi, 50, and 15-year-old Sara Di Vita passed away within hours of each other over the weekend at Cardarelli hospital in Campobasso, southern Italy. 

Investigators suspect the cause of their deaths was food poisoning following a meal the family ate on December 23 in the run up to Christmas.

The menu consisted of mushrooms, fish and seafood, including mussels - dishes traditionally enjoyed around Christmas in the region.

The mother and daughter experienced the same symptoms, including nausea and severe abdominal pain, in the days following the meal.

They were both admitted to hospital, where the teenager died at around 10.30pm on Saturday evening while her mother died a few hours later, on Sunday morning.

The family are from Pietracatella, a small town nestled in the mountainous region of Molise. 

The father, Gianni, who also ate the meal, was airlifted to Rome's Spallanzani Hospital where he is currently being treated in intensive care. 

Antonella Di Ielsi, 50, died a few hours after her daughter on Sunday morning 

Sara Di Vita, 15, passed away on Saturday evening at Cardarelli hospital in Campobasso, southern Italy

Antonella Di Ielsi, 50, pictured with husband Gianni and their two daughters (Sara in centre)

An autopsy has been ordered for the victims' bodies by the Campobasso Prosecutor's Office for Wednesday, to determine whether cause of death was food poisoning or a pre-existing intolerance.

Di Ielsi and Di Vita were both prematurely discharged from hospital twice, on December 25 and 26, before returning on Saturday with acute symptoms.

'We last spoke to Sara on the phone on Santo Stefano (St. Stephen's day),' said Giovanna, Donatella and Giuseppe, friends of the young victim since childhood. 

'She thought the heavy treatment they had given her in the hospital would be enough; she absolutely didn't think her condition could worsen,' they told La Repubblica.

'So much so that we had planned some parties with friends in the last few days. 

'Yesterday we were supposed to go to a birthday party together. She said she would get better soon.'

The Di Vita family is well-known in Pietracatella, with the 55-year-old father - an accountant - having previously served as a mayor of the town for two terms.

The parents' other daughter, 18, was also taken to hospital in Rome, but only as a precaution as she has shown no symptoms and is believed not to have eaten the dinner.