Wollongong City Council will begin drilling boreholes next to North Beach Surf Life Saving Club next week as part of preparatory work for a new clubhouse.
A council spokesman said the existing clubhouse, built in May 1936, was "nearing the end of its useful life" and may need to be replaced.
Load-bearing posts were installed under the ailing structure about five years ago after it was revealed the oldest section of the building was riddled with concrete cancer.
The drilling, to be carried out to the north and west of the existing building, is part of a geotechnical investigation into possible replacements.
The council spokesman said any replacement could allow for an extension of the Blue Mile and might incorporate a seawall, extend the existing promenade or provide further seating.
However, he stressed there had been no decision about if or when the old building would be demolished. He said councillors would vote on any proposal to replace the club.
Last year, the Mercury reported that the council had considered asking private enterprise to demolish and replace the existing clubhouse.
This would allow commercial operations on the site in return for the inclusion of surf club accommodation and facilities.
The council did a similar deal a decade ago with the demolition of the Wollongong Surf Life Saving Club and its inclusion in the City Beach Function Centre complex.
Results from the test drilling will be provided to the council in May.