UPDATED 5.34pm: Labour has decided to initially back the Government's proposed changes to security laws.

Parliament's currently sitting under urgency to debate the first reading of legislation that extends the SIS's surveillance powers and would allow the Government to cancel passports for up to three years

Labour leader Andrew Little says they will back the legislation at its first reading.

Parliament under urgency

Parliament is now sitting under urgency as it consider the Government's controversial foreign fighters legislation.

The Bill grants extra surveillance powers to the SIS, including 48 hour warrantless surveillance, as well as gives the Government the power to cancel passports for up to three years.

SIS Minister Chris Finlayson says the changes are in line with a United Nation Security Council resolution.

"Which urged member states to restrict the movement on foreign terror fighters and ensure that their legislation is up to scratch."