Between four and six-metre swells are forecast between Tuesday and Thursday.
But an in-depth look at the state of the 26-year-old vessel was yet to be undertaken.
"It was a freight-only sailing with eight commercial vehicle drivers and 39 crew on board. There are no injuries and the vessel is watertight."
It comes after a week of failures that raise questions about the country's aging infrastructure.
Mayor Nadine Taylor said the Government needed to ask further questions about how KiwiRail was looking after its ferries.
Brown's comments were not the first time KiwiRail's handling of the Interislander service had been called into question.
It's been confirmed the ship underwent maintenance just weeks ago.
"Just saying."
"Safety is our top priority," the Interislander wrote on their website.
