The founder of Orcon, an internet service provider, says a bill before Parliament requires people to fight for freedom.
About 100 people were at Old St Paul's Church in Wellington on Monday night for a public meeting about the Telecommunications Interception Capability and Security Bill, which further enables spying on New Zealanders.
Founder Seeby Woodhouse said it is not just freedom of speech that people are fighting for, but freedom of thought.
Under the bill, internet service providers would be required to comply with warrants and provide information on customers.
Mr Woodhouse said the bill will add huge costs to businesses like his.
The bill is awaiting a second reading.