The Department for Infrastructure and Transport have started investigation works for the Granite Island Causeway Project.

This is despite the project not yet having received the go-ahead from the Minister for Planning.

The State Commission Assessment Panel met yesterday to hear representations on the proposed project.

Works are taking place on the foreshore on the Victor Harbor side of the existing heritage-listed causeway.

As a result, the boat ramp will not be accessible to the public from 6am on March 1 until further notice.

The works will include underground service location works, geotechnical investigations, flora and fauna surveys, site fencing installation and mobilisation of construction machinery and the construction of a crane pad for undertaking test piles to test noise and vibration and verify pile design.

The department says work will occur intermittently over the coming weeks and will generally take place between 7am and 7pm Monday to Saturday.

It says it will try to minimise the noise disturbance to nearby residents and businesses as much as possible.