THE building touted as the future "heart" of Shellharbour will cost at least $55 million - a price tag the city might not be able to afford according to several councillors.
The business case for Shellharbour City Council's long-planned "city hub" proposes to borrow $15.6 million to help fund the construction, almost as much as the council's borrowing limit.
Council assets including its Lamerton House headquarters would also be sold to raise money.
In the same report, council staff have flagged a possible rates hike to pay for asset renewals as part of the local government's strategy to whip its worrying long-term finances into shape.
Proponents argue the city hub is essential to provide community facilities and replace or improve dated or unsuitable infrastructure, including at Lamerton House and the Tongarra Museum.
It would include a new library and museum, a 350-seat auditorium, council chambers, administration offices, underground parking and meeting rooms.
But the cost will be the major stumbling block at Tuesday's council meeting.
Mayor Kellie Marsh said Shellharbour was already struggling to maintain existing assets.
"If we borrow the maximum amount of money I'm concerned that's going to limit our borrowing capacity for years down the track and ... we don't know what's coming around the corner," she said.
Cr Helen Stewart, who supports the hub in principle, agreed it would come down to funding.
"We have to be mindful that we're charging residents to use our sporting fields and swimming pools," she said.
"It's up to our residents to proof [the proposal] very carefully and if they have comments to ... speak out."
The detailed report identified six design options with price tags between $6.5 million, to refurbish existing facilities, and $70 million, for a building with two extra storeys of commercial space.
Due to lower cost, it recommended one building with 100 basement car-parking spaces but no commercial floors.
It would be on land in College Avenue, bought in 2008 for $4.7 million, and open in 2015.
The staff report found the council could fulfil its strategy of prioritising asset renewal over new assets and still fund the city hub, by balancing cost savings and increasing income.
It also proposed a NSW Treasury "gateway review" to test the rigour of the business case.
General manager Michael Willis said the question for councillors was whether the cost and risk were acceptable.
"The city hub project will act to unify the Shellharbour LGA, by providing essential civic services and meeting spaces ... all in an accessible and central location near public transport," he said.
"The project will provide the civic and community facilities required of the current and future residents, visitors and business operators within the Shellharbour LGA in a co-located precinct."