The Labour Party wants an assurance about the Government's definition of a terrorist fighter before new anti-terrorism proposals become law.
Parliament will go into urgency this afternoon to pass the Countering Terrorist Fighters Legislation Bill.
Labour intended to vote for the Bill, but its foreign affairs spokesperson David Shearer said it disagreed with Attorney-General Chris Finlayson's definition of a terrorist.
Mr Shearer said Labour had a different view and it was debated widely during select committee consideration of the Bill.
"If anybody is going overseas to committ a terrorist act or is going to be partaking with an organisation that is a terrorist defined organisation, then that's the definition. But what we shouldn't be doing is stopping people effectively going and fighting for example in Kurdistan," he said.
Mr Shearer said Labour would ask Mr Finlayson to clarify the matter when the Bill is considered by Parliament today.
The Bill will be passed either today or tomorrow in a rushed process which has given little time for public scrutiny.