Crews fighting fire on Sackville Ferry Road, South Maroota

The fire is now under control.

A NSW RFS spokesman said the fire burnt just over a hectare due to the assistance of the fire-bombing aircraft.

"There were 17 more fire service trucks in attendance and a water-bombing helicopter so they were able to pull that up quite quickly," he said.

"They will remain on the scene for a number of hours so they can continue blacking out and mopping up, just especially while we continue to see these very strong winds through the Sydney area."

EARLIER:

A fire is burning on Sackville Ferry Road at South Maroota, around three hectares in size, and a NSW Rural Fire Service (RFS) spokesman said a water-bombing helicopter was on its way to the site to assist crews tackle the blaze.

The spokesman said there was no property at threat at this stage, and crews were confident the fire could be contained.

"We have dispatched a helicopter just to assist those crews in bringing that fire under control," the spokesman said.

"At this stage those crews are confident they will have this fire contained but obviously the winds are quite strong this afternoon and very dry.

"We're not expecting this wind change also to move through Sydney until later this evening so over the next few hours we can expect these hot and windy conditions and therefore those elevated fire dangers."

The fire is burning in The Hills local government area (LGA), bordering the Hawkesbury.

According to the Australian Bureau of Meteorology, the temperature at 2pm Friday in nearby Wisemans Ferry was forecast to reach 34 degrees.

Wind was forecast to reach 43 kilometres-per-hour at 2pm Friday in Wisemans Ferry, before falling to 11 kilometres-per-hour by 8pm.

Today was the first high fire danger day of the season. Yesterday, the RFS advised permits to burn bush fire fuels would be suspended for Friday.

A NSW RFS spokesman said yesterday: "We are going to see some very high fire danger stretching from Sydney down to the Illawarra Shoalhaven and down to the very far South Coast.

"Temperatures are expected to be in the early to mid 30s with humidity at least 20 per cent, but it's these West North Westerly winds averaging around about 40 kph hour, gusting up as high as 50 kph in most places and maybe 75 kph at high elevations."

Keep up-to-date on the fire at https://www.rfs.nsw.gov.au/fire-information/fires-near-me