Extreme fire danger ratings are in place for Sydney and the Hunter on Tuesday, as well as a swathe of the state’s interior, stretching from the lower central-west plains to the Queensland border.

Temperatures are expected to range from 30C in parts of coastal Sydney to 37C in Penrith, while the mercury is also forecast to hit the low-mid-30s in the Hunter and Illawarra regions and on the south coast.

Those highs are as much as 15C above the October average maximum temperatures for the same locations.

Hot weather is also expected for much of the inland as northerly winds funnel heat into the state from Queensland.

On Tuesday morning, there were 82 fires burning across the state, including 16 that were uncontained.

The largest of the out-of-control blazes was a 820ha bushfire burning in forests at Marengo, west of Coffs Harbour on the north coast.

People in Victoria’s east are being told to leave after an out-of-control bushfire more than tripled in size.

The fast-moving blaze at Briagolong in the Gippsland region covered 5000 hectares on Monday but strong winds have fanned the flames, with the fire stretching across about 17,000 hectares by Tuesday morning.

Emergency warnings have been issued for the surrounding areas, with people in neighbouring Stockdale and Stratford told to leave before conditions become too dangerous.

Those in Briagolong have been urged to take shelter because it’s too late to leave.

More than 650 firefighters are on the ground but wind gusts up to 80km/h are making containment efforts more difficult.

“We’re experiencing spot fires well ahead of the main fire front,” Country Fire Authority chief Jason Heffernan told ABC TV.

“Firefighters are doing their best to try and contain that fire but it is very challenging.”

Communities north of Mudgee in the central west were told on Monday afternoon that it was too late to flee a fast-moving grass fire, which destroyed some buildings and stock before the emergency was downgraded.

NSW Rural Fire Service spokesman Ben Shepherd said concerning fires continued to burn in areas like the Snowy-Monaro region, where a 420ha bushfire was out of control near Bredbo.

Peak wind gusts of up to 100km/h were forecast, which would “push those fires along very, very quickly”, he told ABC radio.

“We could see some rain in parts of NSW maybe later on in the week, but while it remains this hot and this windy we’ve got that elevated fire risk for most of NSW,” he said.

NSW FIRE DANGER

Extreme: Greater Hunter*, Greater Sydney*, far south coast*, north western*, upper central-west plains*.

High: far north coast, north coast, Illawarra/Shoalhaven, Monaro alpine, southern ranges, central ranges*, New England, northern slopes*, lower central-west plains*, northern Riverina, far-western.

*denotes total fire ban