Maritime New Zealand and DNV have now signed off the ferry as ready to sail.
The priority was to ensure the ship is performing safely ahead of next week's planned return to full passenger services, KiwiRail chief executive Peter Reidy said.
"Under international maritime law, an extensive range of rules and regulations govern operational ships, meaning over the last week Maritime New Zealand and classification society surveyors, DNV, have put Aratere through an intense audit schedule to ensure she is safe to resume service."
Aratere would undertake a test run across the Cook Strait today and is scheduled to start carrying passengers from next week.
If for any reason Aratere was not ready for a first full sailing next week, the service was to be replaced by Arahura on the same schedule, said Mr Reidy.
KiwiRail have said the overall financial impact including lost revenue, charter of the replacement ferry Stena Alegra and cost of repairs is estimated to be between approximately $25 million and $30 million.
Watch: Aratere returns to Wellington