Faulty steering technology is being blamed for a Cook Strait ferry running aground in the South Island

The Aratere's been stuck near Picton since late last night because of a steering failure.

Passengers and some crew have disembarked from the vessel ahead of a second refloat attempt on the high tide tonight at 9.

There's no livestock onboard.

KiwiRail chief executive Peter Reidy says he cannot speculate on the cause while investigations are underway.

Transport Minister Simeon Brown says new equipment affected the rudders, and the crew's ability to steer.