The move comes just months after the Dunedin City Council rejected a proposed trial, but groynes advocate Jules Radich has since won the mayoralty and a fresh push has gained traction.
St Clair has historically featured lines of poles that are part of sand-trapping structures known as groynes and Mr Radich argued it should again, to build up the beach.
The council voted 11-4 yesterday to request an urgent report into costs and timeframes of re-establishing a groyne, potentially on a trial basis.
It is expected the council report will collate opinions, reports from experts and provide up-to-date costings.
Mr Radich has suggested the poles could delay expensive work that might need to be done to fight erosion.
He also questioned the performance of geotextile sand sausages, which had cost more than $2 million.
Some scientists have argued the beach at St Clair is the wrong type of environment for a groyne to be effective.
Lee Vandervis was one councillor in favour of the experiment.
A groyne would have amenity value, even it turned out not to be successful in retaining sand, he said.
"We owe it to the community to consider it," he said.
The councillors who voted against were David Benson-Pope, Christine Garey, Marie Laufiso and Steve Walker.
Cr Benson-Pope signalled obtaining consent from the Otago Regional Council could pose a problem.
The council had also approved a management plan in February for the coast from St Clair to St Kilda and this had cost more than $700,000 to develop.
Cr Benson-Pope doubted the wisdom of an apparent deviation from the plan.
Cr Walker asked how much money was too much for an experiment.
Cr Garey said scientific evidence for the benefit of such a project was lacking.
Kevin Gilbert and Bill Acklin were two councillors who lamented lack of action taken in recent years.
Cr Jim O'Malley said experts were not infallible.
Groynes had worked at the beach previously and might again, although damming of the Clutha River was one factor that raised some uncertainty.
