A man has been charged with murder after an alleged fatal assault and house fire on the NSW mid-north coast.

Emergency services were called to a home on Wongala Drive in Coffs Harbour on September 7 about 5.30am following reports of a fire.

Police arrived to find the home well alight.

House fire Wongala Drive Coffs HarbourEmergency services were called to a home on Wongala Drive in Coffs Harbour on September 7. (9News)

A 41-year-old woman escaped the home as firefighters worked to extinguish the blaze.

She was treated for minor injuries at the scene before being taken to hospital.

A crime scene was established.

Shortly after, police were called to a house on Raymond Street in Coffs Harbour, located around 1.7km away, following reports of a double assault.

A couple – a 67-year-old man and a 65-year-old woman – were found at the scene with serious head injuries.

The pair were taken to hospital in a critical condition.

The 67-year-old man died in hospital on Saturday.

House fire Wongala Drive Coffs HarbourA couple – a 67-year-old man and a 65-year-old woman – were found at the scene on Raymond Street with serious head injuries. (9News)

The woman remains in hospital, where she is in a serious but stable condition.

A 28-year-old man was initially arrested and charged with destroying/damaging property with intent to endanger life (DV), and contravene prohibition/restriction in AVO.

Following the 67-year-old’s man’s death, he was today charged with murder and attempted murder.

The charged man was refused bail to appear before court today.