A woman is in custody after two children aged under seven were found dead inside a private home.

The six-year-old and seven-year-old boys were discovered by police at a Coonabarabran property northwest of Sydney in NSW.

Police were called to Emu Lane just after 2pm on Monday to conduct a welfare check.

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A grandmother, 66, was taken to hospital for assessment and remains there under guard.

Authorities say the woman is assisting police with their inquiries and the investigation is ongoing.

“There is no ongoing threat to the community,” NSW Police said in a statement.

“Police are not looking for anyone else.”

A crime scene has been cordoned off at the home and homicide detectives are on their way from police headquarters in Sydney.

Once they arrive, they will work with officers from Orana Mid-Western Police District to piece together just how the two children lost their lives.

Speaking on the tragic discovery, NSW Premier Chris Minns said it was “terrible”.

“What has occurred is terrible and as a state we share in the community of Coonabarabran’s grief at the loss of two young boys who had their entire futures ahead of them,” Minns said.

“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.”

Coonabarabran is a popular destination for star-gazing tourists and has been dubbed the “astronomy capital of Australia”.

The town of 3500 people is a six hour drive northwest of Sydney.