Interislander executives are waiting for results of full investigations into Aratere's grounding near Picton last month, and aren't being drawn on speculation.

The Aratere has now arrived in Wellington, with its post grounding detention notice lifted.

A leaked safety bulletin suggests the ship was accidentally put in auto-pilot before running aground.

Interislander Executive General Manager Duncan Roy says he expects to hear back within the next couple of weeks.

"We've had the black box which has told us the facts - and the fact is the button was pushed,  that's what what we know. We'll wait for the rest of the investigation to go on, so that we know what occurred factually."

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