A family of seven has suffered an Easter morning shock and are "extremely lucky to have survived" after an explosion rocked their home in Sydney's inner west – with six out of seven suffering injuries ranging from minor to serious.

Emergency services were called the house in Ashbury shortly after 7am on Sunday, and police arrived first to find the brick-and-tile split-level home partially collapsed.

A NSW Police spokeswoman said all seven occupants, aged between eight and 73, are believed to have been in the same room – possibly the kitchen – at the time of the explosion.

Two children, aged eight and 12, their 41-year-old father and 38-year-old mother, and three grandparents aged in their 60s and 70s were home at the time, the spokeswoman said.