"We've still got a big job to do to continue the contact with our customers to make sure they get their software updated and aim to continue the job at hand."
Ruddenklau said the amount of time to fix effected vechiles was dependent on updates released from Germany.
"What happens is that model by model the software is developed, it is then passed through an independent third party that tests and verifies that the update fixes the problem and once that happens it is then released in a new wave."
He said the process of signing off software updates was "thorough".
"When it happens we get the information from Germany and we then act on it, get in contact with our customers, get them in and look after them."
Ruddenklau said Volkwagen couldn't be complacent.
"We've learnt a lot managing through this emission crisis here in New Zealand, the primary focus is making sure we look after our customers. I don't think you can ever lose sight of that and probably one of the things I get nervous about is that while it may be 12 months since this erupted, we've got to be very careful not to be complacent and to keep focused on what's important to our customers - the pressure to do that never ends internally and it's something we are pretty determined to achieve."
Last year US regulators found Volkswagen had been cheating in its emission testing. About 482,000 diesel cars were discovered to contain illegal defeat devices which sparked a global recall.
In June Volkswagen agreed to settle consumer lawsuits and government allegations in the US by taking steps that could cost the manufacturer US$14.7 billion ($20.1 billion).