Labour says it has secured concessions to urgent counter-terrorism laws including a shorter period of 24 hours for warrantless surveillance of terror suspects.
Leader Andrew Little said his caucus would decide its position on the Countering Terrorist Fighters Legislation Bill this morning, but it was now likely Labour would support it.
The Foreign Affairs select committee will report back on the bill to the House this afternoon.
Mr Little said the most controversial provision to allow spies to monitor suspects without a warrant would now apply for 24 hours instead of 48 hours and could only be used for anti-terror activities - not for the Security Intelligence Service's broader activities.
Prime Minister John Key yesterday signalled this was one area Government was prepared to change to get cross-party support.
Mr Little also said suspected foreign fighters who had their passports cancelled under the new law change would now be able to get emergency travel documents to return home.
He said the changes were "making the best out of a very bad situation", and also described the rushed law-making process as "atrocious".
His caucus would this morning debate whether the bill had struck a balance between improving security for New Zealanders while not further eroding of rights and freedoms.
"Given the circumstances, we've probably struck that balance," he said.
MPs on both sides of the House had expressed discomfort with some of the legislation's provisions.
During a shortened, four-day select committee process, the bill hit a wall of resistance from submitters including the Law Society, the Human Rights Commission and Islamic groups.
They recommended much stronger safeguards for warrantless surveillance and slammed Government's rush to pass the bill before the end of the year.