Police arrived at a home in Coonabarabran just after 2pm today following reports of a concern for welfare.
Officers then found two boys, aged six and seven, dead at the home.
A woman, aged 66, was arrested at the home and was taken to hospital for further assessment, where she remains under hospital guard.
Police say the woman and children are known to each other and there is no ongoing threat to the community.
Homicide detectives are involved in investigating the deaths.
NSW Premier Chris Minns described the incident as a “tragedy”.
“What has happened is devastating, and as a state, we join the Coonabarabran community in mourning the loss of two young boys who had their whole lives before them,” Minns expressed in a statement.
“I can not begin to imagine the heartbreak their loved ones are currently feeling, including their family, friends, and teachers.
“I thank the local officers who attended the scene for their professionalism and bravery in the face of such a horrible event.”
