Last week the City of Victor Harbor closed access to several boardwalks leading onto the beach between King and Island streets after they were deemed unsafe.

Sand movement caused by high tides left the timber beams supporting the boardwalks dangling well above sand level.

The council's director of environment and infrastructure services, Peter Bond, said the issue has been a concern for some time.

"In the last three to four years, there has been significant erosion of our sand dune system," he said.

"There is now a substantial step down (from the boardwalk), so we've been sealing off the area until it is safe."

Mr Bond estimated eight to ten metres of sand dunes have gradually been eroded.

Last week's high tides reached one metre above predicted levels; again forcing the sand dunes back several metres.

The manager of open spaces, Brian Doman, said the situation has been getting worse each year.

"At the moment we're not getting the sand build-up where we really need it," he said.

The council plans to sand bag the area once the tide drops off later this week.

"We have serious concerns for the area and with a further rise in sea levels predicted, it could get worse," Mr Bond said.

The council is seeking funding from the state’s marine branch for sand replenishment over the next three years.

Funding was received in the last financial year to source sand from the Encounter Lakes development, but lapsed as it was not up to specification.

"We need to do something, otherwise we will lose the dunes back to the parklands and we'll be in serious trouble," Mr Bond said.