Claims by civil libertarians that authorities may pass on information and photographs of G20 protest groups or Brisbane citizens to foreign spy services are wrong, Queensland police say.

The Queensland Council for Civil Liberties (QCCL) last week raised concerns about foreign services being given information and images during next month's G20 summit.

Leaders from the world's major powers will be visiting Brisbane for the summit.

Thousands of police officers on duty will have the power to exclude people from a large area of Brisbane and take their photograph to share with all police on duty.

QCCL spokesman Terry O'Gorman said last week that by law, the photos would go to ASIO and the Immigration Department and possibly foreign intelligence services from countries, including Russia and China

But G20 Group Assistant Police Commissioner Katarina Carroll said that would "not be the case at all".

"That's not in the legislation - we would never do that to our protest groups, nor would we do that to the public in Queensland," she said.

"We have that information for our purposes and that would not be passed onto other countries - it would not be in our best interests to do that and we would not do that.

"We've established a trust relationship with these [registered protest] groups - we have a transparent process that we deal in, and that's the way it'll be maintained during G20."

However, section 86 of the G20 (Safety and Security) Act 2013 on pages 66 to 67 in conjunction with Section 52 and 57 allows for police to take photos of members of the public who have been excluded from the declared zone and for those photos to be shared with a Commonwealth agency and foreign governments.

Some activists planning chaos away from G20 zone

Assistant Commissioner Carroll also said police were aware some activists were planning to create chaos and might target other parts of Brisbane because they would not be able to access high-security zones.

"Some of them are well known... but it's probably not up to me to reveal groups because really it's their agenda that they want to put forward, so it's up to those groups to come forward themselves," she said.

"It's a group that advocates because the security layer is so tight around G20 and if you can't cause damage in those areas, to obviously take that damage elsewhere other than the G20 area."

She said 24 peaceful protests had been registered with police and all groups were welcome to consult.

"There's such a distinction here - there are some really genuine groups and I've got to thank those groups that we've been working closely with - and our consultation with those groups has been going on now for two years.

"However there are some groups that just advocate damage and mayhem and from our point of view it actually damages their cause even further.

"I don't know whether they have a stated aim or are really wanting to achieve anything other than mayhem at such an event and on the world stage."

Assistant Commissioner Katarina Carroll said police were expecting peaceful demonstrations but were ready to dismantle crowds if things escalate.

"We've been very, very clear from the outset that if there is damage, or if anyone is hurt, or if there is destruction during the event, that we would be very affirmative and swift in our action if that is to be the case," she said.

Queensland police will also issue exclusion notices to at least two members of the public ahead of the Brisbane summit.

Police were give extra powers to compile a 'prohibited persons' list for those known to cause trouble at major events.

So far only two names were on the list, but authorities said more could be added in the next few weeks.

Queensland Police Union (QPU) president Ian Leavers was briefed this morning by the deputy and assistant commissioners overseeing the G20.

He said police could not be better prepared.

"We're confident that the work that has been put in by police over the last two years, that they will handle any situation that will arise," he said.

"Obviously there may be some protesters - no-one can predict what will or won't happen. but let's say we're as best as prepared as what we possibly can be at this point in time."