The report comes almost nine weeks after the Queen dredged sand from outside the South Channel, near Hovell Pile, about three kilometres off the coast of Rosebud.

The dredger worked outside the prescribed area for about 100metres, which took about

90 seconds, on April 19 but

the OEM was not notified until May 8.

Environmental Monitor Mick Bourke was believed to be annoyed about the late notification and asked the Port of Melbourne Corporation for a full report.

The port corporation initially told Mr Bourke there was no evidence of environmental damage.

On May 13, Mr Bourke said the OEM had requested information on the incident to help inform its advice to project regulators on the environmental performance of the dredging project.

"We asked PoMC for information ... about the non-conformance, what actions were being taken to address the circumstances that led to the non-conformance, confirmation of the impacts and potential effects on the environment, and the timeline of events between April 19 and May 8," Mr Bourke said.

"My role as the Environmental Monitor requires me to investigate all environmental management plan non-conformances and provide my findings to the project's regulators and the Victorian community."

Last Wednesday, Mr Bourke said he was "satisfied with the information provided by PoMC and investigations by the Office concluded that because the incident occurred within the existing shipping channel, the environmental impacts ... on the bay's plants and animals were negligible".

"Prevention is better than cure and our main focus was to understand how the incident occurred and whether or not any changes needed to be made to dredging operations to help prevent it from happening again during the remainder of the project. The Office did not consider that project-wide changes needed to be made."

Turbidity monitoring data for June 15-21 showed low turbidity across monitoring sites in Port Phillip, Mr Bourke said.

Reports and latest monitoring data are at www.oem.vic.gov.au