There is 'very high' fire danger in place for the Illawarra on Monday but fire crews are gearing up for another potentially dangerous day on Tuesday.

The Green Wattle Creek fire burning near Oakdale is at advice level as is the large blaze at Currowan.

Conditions eased across the fireground on Sunday allowing crews to slow the spread of fire and undertake backburning where possible.

Read more: A special kind of courage: Illawarra firefighters turning out in force

At 9pm, there were five fires which remained at Watch and Act level across the state with 91 bush and grass fires burning across NSW and 48 are still uncontained.

Crews worked hard locking in containment lines, being supported by aircraft and heavy plant as well as making roads safe to try and re-open them.

Several community meetings were held to give updates to residents on the current fire situation and what they should do to prepare, ahead of increased fire dangers on Tuesday.

NSW Rural Fire Service said fire danger rating was set to increase on Tuesday with hot, dry, windy conditions and very low humidity forecast in the Illawarra.

The mercury in Wollongong is expected to reach 33 degrees on Tuesday with wind and areas of smoke haze likely.

In the Albion Park area, the temperature could hit 35 degrees.

In both areas, southerly 25 to 40 km/h winds are expected in the middle of the day.

Air quality on Monday was 'good' and there was no total fire ban for the Illawarra on Monday however the RFS could update that warning for Tuesday.

RFS is reminding residents to take the time now to discuss their bush fire survival plan and know what you will do if fire threatens.

Residents, if they plan to stay and defend their property, should be prepared with the right clothing to protect themselves from heat and embers.