Alex Stojanovski owns The Pantry in North Wollongong and is turning the old post office at Thirroul into a restaurant called Postman's Quarter.

Mr Stojanovski doesn't expect Tuesday's Federal Court decision to dismiss an appeal against a cut to penalty rates will make much difference.

The ruling upheld the Fair Work Commission decision to cut Sunday penalty rates for casual employees covered by the Restaurant Industry Award from 75 per cent to 50 per cent.

"I don't think it's the wages that is the main thing that keeps people closed on a Saturday or a Sunday," Mr Stojanovski said.

"I think it's more the clientele that they target. But there may be more of a disposition to open on these days because of the lower penalty rates.

"You may get to see a few more places open but it doesn't necessarily mean there's more diners out there though."

He suggested restaurants might start to stay open over the weekend but felt that would be a reaction to the warmer months rather than a cheaper wages bill.

Mr Stojanovski said he might opt to open The Pantry longer on a Sunday, but the penalty rate reduction hadn't changed his staffing plans for Postman's Quarter.

"We staff according to what we think we're going to do in terms of customers," he said.

"We try to overstaff rather than understaff.

"If a restaurant capacity is 100 people and you can comfortably do 100 people with four or five floor staff and one or two behind the bar, it's not necessarily essential to put more people on."

Illawarra Business Chamber chief executive Debra Murphy applauded the decision as a way to help end the "ghost town effect".

"This is a win for many small businesses in the region in the hospitality sector who can now afford to open their doors on a Sunday," Ms Murphy said.

"Hopefully this will bring an end to the 'ghost town' effect, particularly in smaller communities, on a Sunday where it's actually more cost-effective to close rather than open the doors and be crippled by exorbitant hourly rates."

She said she expected the decision would mean Illawarra cafe owners would look to employ more staff and extend workers' shifts.