Hundreds of owners of the country's biggest selling electric vehicle are waiting on Nissan to respond to concerns about the battery, months after problems were first identified.
In March, research by an electric transport community group, Flip the Fleet, found that the battery health of the newer 30 kilowatt Nissan Leaf cars could be degrading at a faster rate than the older model.
The group revealed the batteries are degrading at about three times the rate of a 24 kilowatt version.
Its founder Henrik Moller said the cause was unclear.
"The big mystery is the battery chemistry," he said.
"We don't know exactly what was changed in the chemistry of the battery."
Chief executive of the Imported Motor Vehicle Industry Association David Vinsen said it could be heat related.
"It may be related to previous hard acceleration, as an example, or hard use, or continued rapid charging."
Mr Moller said buyers of any electric vehicle should always get a battery scan before purchasing.
Nissan said it is reviewing the research, and didn't know when it would be completed.