Two bodies, believed to be those of children, have been found inside a Blue Mountains home destroyed by a fire which four other children and their father managed to escape.

The family of six children, aged from three to 16, and their father, who is in his 30s, were inside the home in the small town of Bowen Mountain in the foothills of the Blue Mountains when the home caught fire in the early hours of Monday morning.

The family was due to move to Queensland on Monday, police said. The mother was already on her way to their new home and so was not inside when the fire struck.

Emergency services were called to the home just after 2.10am, arriving around five to eight minutes later. About 60 firefighters from Fire and Rescue and the Rural Fire Service were needed to bring the blaze under control.

NSW Fire and Rescue assistant commissioner, Andrew Faunce, said during a press conference on Monday morning that firefighters were unable to enter the home because of the intensity of the blaze. Neighbours had also tried to help before fire fighters arrived.

“We had a very, very fully developed fire at the point in time, and with structural collapse already occurring through the roof cavity, it was just deemed too unsafe for firefighters to make entry, to conduct any kind of rescue or search at that point in time,” Faunce said.

“Firefighters at the time, deployed some defensive measures and and started to bring the fire under control … And then after about 3:30am this morning, firefighters went into a more of an offensive searching of the premises as well.”

Police superintendent Nadine Roberts said two bodies were located, one upstairs and another downstairs, “believed to be that of the two children”.

“As you can appreciate, it, is a coroner’s investigation, and we can’t confirm those details until a formal investigation has taken place,” she said.

Roberts said the four other children and their father were in hospital being treated for smoke inhalation and minor burns, “but otherwise they are okay.”

The mother was on her way back to be with the family, police said.

Emergency services were still investigating the cause of the fire and said late on Monday morning it was not being treated as suspicious.

“Our thoughts and prayers are with the families, with the siblings and with the broader community,” Roberts said. “It’s an incredibly confronting situation, not only for the community and the families, but also the first responders who had to attend.”