Work on a $5 million internal revamp begins next week and will be followed by another $5 million worth of construction next year.

It will allow the club to boost its 16,000 membership to 50,000 and make space for up to 60 new poker machines.

"We need to get into the 21st century," chief executive officer David Whyte said. "A club needs to reinvent itself every seven or so years and we're overdue."

This year's work will take place in five stages and is due to be completed by September. Amendments to smoking and gaming legislation were design factors.

Mr Whyte said no decision had been made to increase the number of poker machines even though there would be space for more.

"We'll have the space for 260 machines, we've got a licence for 241 and at the moment we've got around 200 so, yes, it may all change," he said.

Wests Illawarra Leagues Club has 261 machines, the most in the region.

The Shelly's board has also commissioned a consultancy firm to determine whether club grounds could be used to capitalise on the expanding Shellharbour area.

Options include a fitness, child-care or medical centre.

The existing club building takes up only 10 per cent of the site.

Mr Whyte stressed land would be leased, not sold.

"This land could better cater for what the community needs," he said.

"When a new medical centre opened in Shellharbour a couple of years ago it was estimated it would reach capacity in two years but took three months."

This year's work includes the new gaming area, as well as a new lounge, foyer, restaurant, outdoor bar and refurbished internal bars.

Next year, the ground-floor bar, kitchen and service area will make way for a noodle bar and pizza and pasta restaurant.