Four members joined up with the Upper Hunter strike team at the Sir Ivan Fire this morning.

Residents of the towns of Uarbry and Turill, north of Mudgee in the state's central west, have been told to leave their homes now after the fire breached containment lines.

The Rural Fire Service issued the emergency warning just before midday, telling residents to head towards the town of Cassilis.

The Cassilis RFS Brigade warned followers on its Facebook page just after 1pm to pay close attention to official reports.

“The situation has turned serious,” the post said.

“The Cassilis area is being affected by the fire at Leadville – not yet directly, but areas in Turill and Uarbry are under emergency alert.

“Pay close attention to official reports and review your bushfire survival plans; be prepared to put them into effect.

“Options available would be to stay in your home if well prepared, leave and stay with friends and family in Merriwa or evacuate to the Cassilis Park Trust grounds near the bowling club.

“Going in the Coolah direction is no longer an option...roads towards Ulan and Coolah are no longer safe to travel.”