A firefighter has been injured as a strong wind change brings 90km/h wind gusts to dozens of dangerous fire grounds in southern NSW.

The male firefighter in his 20s suffered burns to his face, ears and hands in the Snowy Valley region where fierce winds were pushing the fires in different directions.

Communities on the Victoria-NSW border were warned they may be unable to contact triple zero due to telecoms outages as the 233,000-hectare Green Valley fire reached emergency warning level on Friday evening.

EMERGENCY WARNING Dunns Rd & East Ournie Ck (Snowy Valleys LGA) Strong S change causing fires to flare up. Fire is burning towards the areas of Ournie, Mannus and Tumbarumba, seek shelter if the fire impacts. Areas around Mt Adrah & Tumblong may experience smoke and embers. pic.twitter.com/JtpWxlqmCM — NSW RFS (@NSWRFS) January 10, 2020

Watch and Act - Erskine Creek fire (Blue Mountains LGA)

Fire activity is increasing south of Wentworth Falls. A southerly change due after midnight will push fire towards Leura & Wentworth Falls. Monitor changing conditions. Know what to do if fire threatens.#nswrfs #nswfires pic.twitter.com/XZsyQUcLG8 — NSW RFS (@NSWRFS) January 10, 2020

The blaze jumped Jingellic Road at Lankeys Creek and is moving to Mundaroo, Tumbarumba and Mannus.

Another nine blazes - including the massive Dunns Road and Border fires - were at watch-and-act level on Friday evening, with most in the state's scorched southeast.

The southwesterly wind change brought gusts of up to 90km/h across the Riverina, with a gust of 76km/h also recorded at the Alpine town of Cabramurra.

NSW Rural Fire Service - Fires Near Me

It will blow up the coast throughout the evening and was expected to reach Morouya at around 11pm and Sydney by 2am on Saturday.

At Thredbo, snowmaking machines have been running non-stop for days to wet village grounds to combat any potential spot fires from the Pilot Lookout fire south of the ski resort.

Meanwhile, an emergency warning was downgraded for the Yearinan Station Road fire near Coonabarabran in the state's north.

NSW Rural Fire Service Commissioner Shane Fitzsimmons said the Yearinan Station Rd fire and another in a remote region of the Blue Mountains were new.

He said it appeared they had begun due to lightning strikes.

Watch and Act - Dunns Rd, East Ournie Ck & Yellow Bog Rd fires (Snowy Valleys LGA)

Fires are burning on multiple fronts. There may be erratic fire behaviour. If you plan to leave, or are not prepared, leaving early is the safest option.https://t.co/sS5OxzJy2M#nswfires #nswrfs pic.twitter.com/j0bxc1empa — NSW RFS (@NSWRFS) January 10, 2020

Premier Gladys Berejiklian earlier urged communities to remain vigilant amid warm and windy conditions.

"In essence, we know it's going to be a long and difficult night," Ms Berejiklian said.

"We won't know the extent of the impact of these fires until early tomorrow morning."

An EMERGENCY WARNING is being re-issued for Buchan, Buchan South.

For residents north of Mackiesons Road, shelter in place. It is too late to leave.

For residents south of Mackiesons Road - leaving now is the safest option.

More details at https://t.co/dvwvXWaxQJ#vicfires pic.twitter.com/yeJyxMG84f — VicEmergency (@vicemergency) January 10, 2020

Authorities fear large blazes on the NSW South Coast could merge, creating a fire front that stretches from south of Mittagong to north of Bega.

Fires in the Snowy Valley - which have burnt through an area half the size of Sydney - are also close to merging.

About 65 of the 137 bushfires burning around NSW are uncontained.

AAP

Conditions are due to ease later on Saturday with showers and isolated thunderstorms in coastal parts and adjacent ranges expected, Bureau of Meteorology spokesman Grahame Reader said.

"These are probably not significant falls. There could be heavier falls locally but that won't be widespread."

Prime Minister Scott Morrison said the navy ship HMAS Adelaide remains on stand-by off the Eden coast and is assisting with resupplying.

AAP

Australian Defence Force national coordinator Major General Jake Ellwood on Friday said just under 2000 reservists are on duty to provide support during the bushfires.

The number of homes confirmed destroyed since January 1 has increased to 1079, the RFS said on Friday.

At least 1995 homes have been lost since the start of the fire season. Another 816 have been damaged.

Since July, 20 people including three firefighters, 6200 livestock and millions of wild animals have died in the NSW bushfires.