Laws allowing spies to intercept text messages, snoop on computers and track people online will be pushed through Parliament before next year's Rugby World Cup.

The move has brought accusations that the Government is passing laws behind closed doors.

But Prime Minister John Key says the bill must be passed before the start of the cup tournament, which many world leaders will be visiting.

"We're not predicting instability but we have to have the right legislation in place," he said.

His decision on the Security Intelligence Service Amendment bill side-steps the advice of the Privacy Commissioner that of review of the security laws should take up to three years.

Parliament's security and intelligence committee, chaired by Mr Key, is expected to accept public submissions on the bill, but hearings will be held in private for security reasons.

"It won't be in the public interest to have it open, for a whole bunch of reasons I don't want to go into," Mr Key said.

One MP yesterday said the move was unprecedented and offensive, claiming drunken fans would be the biggest problem at the World Cup.

The bill, which will be introduced on Thursday, aims to update the 41-year-old law on how warrants for SIS agents can be granted for actions such as intercepting text messages, monitoring computers and spying on people online.

It will specify electronic tracking as well as what the SIS can target, including telephone lines, accounts, emails, computers and IP addresses, user account names and other documents.

It is separate from the Search and Surveillance Bill, which updates the way law-enforcement agencies, such as police, can gather intelligence.

Mr Key said the rules on granting intelligence warrants for the SIS needed to keep pace with technology.

He would not comment on how the bill might affect SIS operations, citing national security.

The SIS employs about 220 staff, and its budget is $38 million.

The threshold for granting warrants will not be changed, and Mr Key did not expect the bill to affect the average number of warrants - 11 to 15 - granted each year.

The present law has a rule of general permissibility, allowing SIS agents to do what is otherwise illegal if it is to protect national security.

But the Bill of Rights, which protects people from unreasonable search and seizure, meant the law had to be made more specific.

Green MP Keith Locke yesterday said he would make submissions to the security and intelligence committee and it was "offensive" that the public would be shut out from the hearings.

"New Zealanders should be worried that proposed changes give the SIS more power to covertly intercept communications, invade computers, and put tracking devices on people's cars.

"The main security problem for the World Cup will be drunken fans, which is best dealt with by restricting the supply of alcohol, not restricting our civil liberties."

Police submissions to parliament also cited drunken hooligans as a greater threat than al Qaeda to the running of the World Cup.

Mr Locke said rushing the bill into law implied that the new powers would be used for World Cup-related security operations.

The bill would allow the SIS to spy on foreign communications and be free from liability. Protection from liability now applies only to domestic warrants.

To balance this, subjecting foreign warrants to approval from the Commissioner of Security Warrants has been floated. Currently the commissioner's approval is needed for domestic warrants, but not foreign ones.

In a regulatory impact statement, Law Commissioner Warren Young said the changes would have privacy consequences, but that was "clearly justified by the associated benefits".