Council estimates planning and construction of the Minnamurra Boardwalk and Cycleway will cost $9.5 million.

Council does not have the funds to proceed with the full project, initially priced at $4.5 million.

"Council is yet to decide whether to proceed with building the boardwalk," a council spokesperson said.

"Council would need to secure further funding from the NSW government (or Australian government), beyond the $4.5 million initially provided, before any such decision is made."

At this stage, council has resolved to dedicate $30,000 to the project.

Read more: First stage of Minnamurra Rainforest upgrade now open

Meanwhile Jamberoo resident Graham Pike has urged Kiama Councillors to push the red button on the project.

"Cardno’s boardwalk design work is only 35 per cent complete and the council cost estimate for designing and building the project has nearly doubled from $4.5 million to $9.5 million," Mr Pike said.

"Perhaps this debacle would not have occurred if there’d been due process and proper council consideration in the first place.

"It has occurred and there’s a $9.5 million train-wreck about to happen.

"My plea is to a majority of Kiama councillors to stop the obscene budgetary bleed of public funds - and the boardwalk project - at the next council meeting on March 19."

Council has defended its expenditure on the project to date.

"A significant portion of the expenditure was for environmental studies required by the relevant statutory authorities," a spokesperson said.

Kiama Council will host a special meeting on March 26. 

Mr Pike is sceptical of council's reason for holding the meeting.

"Council is having a special meeting intended to approve the boardwalk before it can come under new, more rigorous NSW government environmental protection legislation which comes into effect on April 3," he said.

Kiama Council maintains the meeting is to consider the potential environmental impact of the boardwalk on the marine estuary.