The Prime Minister was targeted by all three Labour Party leadership hopefuls at a meeting in Hamilton on Thursday night.
About 250 party members attended the meeting to hear Grant Robertson, Shane Jones and David Cunliffe speak. Each spoke for 10 minutes before questions were taken from the floor.
Mr Jones said John Key has sold the country out.
Mr Robertson said the Government is running roughshod over democracy and people's democratic rights.
Mr Cunliffe said Labour needs to inspire the 800,000+people who did not bother to vote in 2011.
Party members were able to cast their vote in a ballot box or go online to vote.
There are two meetings on Saturday, in Nelson and Wellington.
The final meeting is in Christchurch next Tuesday and the result will be announced on 15 September.
