A civil rights liberty group says proposed additional powers for police at Apec 2021 amount to foreign autocratic tactics.
The Asia Pacific Economic Cooperation 2021 Bill is designed to support New Zealand's security preparations for hosting APEC.
Up to 20,000 visitors are expected to descend on the country for the event including world leaders, ministers and international media.
The bill enables police to draw on members of the New Zealand Defence Force to bolster their ranks.
It allows police to secure Apec venues, close roads and restrict movement in marine areas.
NZ Council for Civil Liberties spokesman Thomas Beagle said he was worried these cordons could also double as a means to keep protesters at bay.
"We're seeing that as being a Trojan horse, because if you're blocking people out for security, you're blocking people from protest as well."
Beagle was also concerned about powers for police to close privately owned places for days in the name of security, which he said could interfere with people's privacy and deprive them of their property and right to housing.
During the Bill's first reading Foreign Affairs Minister Winston Peters said he understood some members of the public may want to assemble and have their voices heard during the Apec year.
"The right to do so is fundamental to our democracy and not challenged by this legislation."
The number of high-profile people visiting meant a tailored security approach was necessary, Peters said.
"When we last hosted Apec in 1999, the world was a considerably different place. We don't need to outline the many international new and local incidents that have scarred our world and compelled us to think more stringently about security and the what-ifs."
The Bill allows police to search homes within a security area or secure transport route to search for risks to security, although they would need a warrant or consent from the property occupier to do so.
Beagle said it was unreasonable for properties to be searched for no other reason than their location.
In a written submission to a select committee on the bill the NZ Council for Civil Liberties said New Zealand was the stronger democracy and it had a responsibility to lead.
"Instead, this bill proposes for us to adopt anti-democratic measures which would drag us down to the lowest common denominator."
The bill passed its first reading in November but without support from the Greens.
Greens justice spokeswoman Golriz Ghahraman said the security measures proposed would impinge on human rights and civil liberties.
The bill allows for certain foreign protection officers to carry firearms subject to conditions the Police Commissioner might impose like the type of weapon.
Ghahraman said that was an overreach.
"We see it, in particular, as unnecessary and counter-productive while New Zealand is itself undergoing reform of gun regulation."
She was also concerned about foreign agencies being allowed the use of wireless electronic countermeasure technology to distort technology being used in a threatening way such a cell phone-operated bomb.
"So these are the privacy rights of ordinary New Zealanders or visitors to this nation during the summit — to have their movements tracked and known, their devices accessed in ways that we are not going to be regulating."