The Auckland man who lost three family members in a horrific house fire last month has died.

Refugee Council of New Zealand secretary Kailesh Thanabalasingham, 47, escaped the blaze in Flat Bush on December 22 but was severely burnt. 

Family spokeswoman, barrister Deborah Manning, confirmed Thanabalasingham​ died at Middlemore Hospital just before 7am.

"The family are obviously devastated and asked for privacy. It's a devastating shock."

Family were with Thanabalasingham when he died, she said.

She was unsure if Thanabalasingham's daughter had been told of her father's death.

"As you can all imagine this is just very new information."

The fire claimed the lives of Thanabalasingham's 5-year-old son Bareth Kailesh, 39-year-old wife Bhamini Theiventhiran and 66-year-old mother-in-law Umadhevi Theiventhiran.

Thanabalasingham was heavily sedated after the fire and was not able to attend the funeral of his family members at the Manukau Memorial Gardens this month.

It is understood he was not aware of the deaths of his son, wife and mother-in-law.