Image: Twitter/Steve Hart

A man is accused of pulling a knife on police and assaulting a firefighter who were responding to a house fire in Sydney’s north-west.

Emergency services were called to a house fire on Tallawong Road at Rouse Hill, just before 1am.

When they arrived, police had to stop a 40-year-old man who was trying to re-enter the burning house.

A 40 year old man is under police guard in Blacktown Hospital, accused of setting a house on fire at Rouse Hill, pulling a knife on a police officer and assaulting a firefighter. The home has been destroyed. @9NewsSyd pic.twitter.com/0iTm0RmhgQ

— Tiffiny Genders (@tiffgenders) August 28, 2019

The man allegedly armed himself with a knife as officers tried to speak with him and assaulted a firefighter.

Police were forced to taser and capsicum spray the man, with half a dozen officers needed to carry him away from the scene.

The 40-year-old has been taken to Blacktown Hospital for a medical assessment and remains there under police guard.

The house was completely destroyed by the fire which is believed to have been deliberately lit.

Investigations are continuing… more details to come.