The property industry says it remains "in limbo" as the state government reviews the future of the Newcastle Mines Grouting Fund.
The Property Council called two years ago for the government to confirm it will continue the scheme, which was set up as a pilot in 2015 to accelerate development with money from the Hunter Infrastructure and Investment Fund then extended in 2018 until the end of 2022.
The $17 million program acts as an insurance policy for developers and investors embarking on multi-storey projects which require an unknown quantity of concrete grouting to be pumped into old mine workings.
Developers pay for grouting up to a capped cost of several hundred thousand dollars, depending on the site size and location. The fund covers the rest, if required.
Property Council regional chair Neil Petherbridge said the review was proceeding at a "glacial pace".
"It's no use telling us in December. The industry needs to know sooner rather than later," he said.
"They've said they'll try to give us six months' notice, but there doesn't seem to be much urgency."
Federal Labor has committed to extending the fund to cover Lake Macquarie if it wins next month's election.
Only a fraction of the $17 million has been used, but Mr Petherbridge said the fund had allowed developers to access bank finance.
He said the Newcastle Art Gallery expansion and University of Newcastle's Alumni House in King Street were two projects now seeking guarantees under the fund.
"There's been a bit of talk that it was just designed to be a stimulus for development, but the day it goes no one will get finance," he said.
"Banks want to know whether the grouting will cost $200,000 or $2 million."
Mr Petherbridge wants the scheme, which is administered by Hunter and Central Coast Development Corporation and covers only inner-city Newcastle, extended to the rest of NSW.
He cited an aged care centre and private hospital at Charlestown and industrial sites in Cardiff among projects which would like access to grouting guarantees.
Analysis prepared by Lake Macquarie City Council's economic development corporation estimates that the fund could help speed up or unlock $453 million of investment in Charlestown alone.
The program is also meant to fund underground investigations and a cost-effective grouting strategy for Newcastle, but Mr Petherbridge said this objective appeared to have fallen off the government's radar.
