At least 700 submissions have been lodged so far to the inquiry, with about half from people in Rochester.
Typically, a parliamentary inquiry receives about 200 to 300 submissions.
Campaspe Shire Mayor Rob Amos said it was “vital that the voices of Rochester are heard” and encouraged those who were yet to lodge a submission to consider doing so by the extension deadline.
“Although people across Campaspe Shire were impacted by the flood event, Rochester and surrounds were the hardest hit,” Cr Amos said.
“More than 800 homes were either damaged or uninhabitable, and most residents are still not back in their home some eight months after the event.”
He said it was important for the Victorian Government to not only look at statistical data about asset loss but to hear the stories of how people had been greatly affected.
People outside Rochester will still be considered on a case-by-case basis.
The new date for submissions to be lodged is June 28.
Later this year the inquiry will kick off a series of public meetings to hear first-hand from people affected by the floods.
The first hearing will be in Rochester on Wednesday, August 23, with one in Echuca the following day.