While it sits in rainforest, the Illawarra Fly wasn't hit by fire - though the approaching Morton bushfire was a cause for concern.

The treetop walk and zipline may not have been turned to ash and rubble, but the business has felt the effect of the bushfires.

Manager Andrew Zentrich said revenue is down 46 per cent compared to last year.

In December visitor numbers fell by 1000 and, between Christmas and now, they've dropped a further 3000.

"While we haven't had fires on-site," Mr Zentrich said, "we've definitely been affected in terms of volume and revenue.

"We wanted to have a good December and January to kickstart the year but now it's going to be very hard for us to make up that deficit throughout the year, especially starting so slow in January."

The business has been feeling the pinch since November, closing four times during Catastrophic fire conditions.

READ MORE: South Coast businesses broke after bushfires

Even though there weren't fires in the region at the time, there was smoke. When a large part of your business involves expansive views, having them covered up with bushfire smoke is a problem.

When the fires did hit the South Coast, they took away a large market for the Illawarra Fly - people from the Shoalhaven area would regularly come up over the summer period.

"But given the circumstances, we didn't see as many of those people visiting because of road closures and things like that," Mr Zentrick said.

"We had a good week right around New Year's but everything else has been pretty slow and that has primarily been driven by the fire and people not travelling."

While visitor numbers are down thousands, Mr Zentrich said some people are still coming to have a look.

"There are still people on holidays and we're still getting our little pocketful of locals as well," he said.

"In that big fire period, when a lot of stuff was happening in the South Coast, a lot of our visitors were internationals, which is a different demographic for us.

"They usually make up only about 5 per cent of what we get through the doors, but in December they were making up 12 to 15 per cent of our visitors."

Meanwhile, while the wet weather might not help visitor numbers at the Illawarra Fly, it's around for a while.

Wollongong copped a drenching on Thursday night and more rain is expected over the weekend.

Things will warm up by the end of the week, with 34 degrees predicted for Thursday.

Nowra got 30mm of rain through to Friday morning and should see more rain throughout next week.