Labour is promising to delay as much as possible the passing of legislation giving the Government Communications Security Bureau legal powers to monitor New Zealanders.
While Labour will use delaying tactics when the GCSB Amendment Bill is debated clause by clause on Tuesday, it accepts it will become law with the support of the independent MP, Peter Dunne.
Despite this, Labour leader David Shearer said the party is proposing a change so that a proper review of New Zealand's spy agencies is held and then new legislation introduced within 12 months.
Mr Shearer said the Green Party supports the amendment, but Labour has not yet talked to other parties.
Radio New Zealand's political editor said the changes will tighten the oversight of the GCSB, but critics of the legislation say it will still enable the bureau to intrude on people's privacy.
On Monday, Prime Minister John Key said most New Zealanders are not hugely worried about the bill.
Council of Trade Unions president Helen Kelly said that is not true, but most are feeling powerless to do anything about it.
"There is a very strong narrative in New Zealand that people should be deferential to powerful organisations and powerful people and this incredible deference is actually now damaging our whole society and our whole community."
Ms Kelly said the bill moves New Zealand towards becoming a police state.