In April the council said it had exchanged contracts for the sale of a 42.25-hectare parcel of land at Tullimbar to help fund the $59.5 million Shellharbour City Hub project.

Some councillors and the Stop the Hub community group expressed concern the property had been sold through "a put and call option".

In May council staff said the deposit and first instalment had been received, but the balance would be received over the next two financial years.

Last week staff corrected that date, saying the final amount would be received in the 2017-18 financial year.

Cr Peter Moran said though staff would argue the money would not be required for the hub until a later stage, no one was talking about the opportunity costs of the method of sale.

Last month Cr John Murray said the interest earned on the $4.05 million sale of the current Warilla library site, sold along with the former council chambers, was helping to cover the costs of leasing back the library.

Cr Peter Moran said he had tried to unsuccessfully to have the council examine the opportunity costs of the method of sale.

"If we invested the $13.3 million when we sold the property, we would be earning interest," Cr Moran said.

"No council officer is prepared to acknowledge the fact we have dudded ourselves out of a million dollars in interest by entering into this put and call option," Cr Moran said.

aarnold@fairfaxmedia.com.au