Civil libertarians are infuriated at special regulations coming into force for the upcoming Catholic World Youth Day event in Sydney, Australia, where Pope Benedict XVI will be the guest of honour.
Legal experts say that restrictions will effectively make it illegal to dissent from the event, and have already described them as "draconian, repugnant and unnecessary".
They claim the regulations could see situations such as someone deemed to be wearing an offensive T-shirt being arrested and given a hefty fine.
Green, student and atheist protestors against the Pope say they will mount a legal challenge and a campaign of civil disobedience if necessary.
According to news agencies, New South Wales Police say the measures are designed simply to ensure that World Youth Day is a peaceful and happy event.
The event is due to run from 15-20 July 2008, but from today until the end of the month the regulations have already come into force.
Under the regime SES and Rural Fire Service volunteers will assist police in bag checks at World Youth Day locations. Anyone deemed to be causing annoyance could be arrested and fined up to Australian $5,500.
New South Wales deputy police commissioner Dave Owens says the regulations do not restrict democratic rights.
"If people wish to lawfully protest, we will facilitate those protests as long as they are law abiding," he declared.
"Police officers always maintain a discretion, and I expect them to use that discretion."
There have been suggestions that people could be arrested if they wear a T-shirt that promotes the use of condoms. Mr Owens refused to rule that out.
"There are individual circumstances that will have to be dealt with individually," he said.
President of the New South Wales Bar Association Anna Katzmann says she does not understand why the regulations have been brought in.
"The Government has by-passed the normal parliamentary scrutiny that would be available if they were introduced by an Act of Parliament," she commented. "They are also an unreasonable interference with people's freedom of speech and movement."
Ms Katzmann says there is a chance people could be arrested for trivial offences in the areas that have been declared as special World Youth Day zones.
"These World Youth Day-declared areas are numerous and they encompass places like Sydney University and the Opera House. Places that you and I would travel to regularly, not just churches or church schools," she added.
New South Wales Council of Civil Liberties president Cameron Murphy is also opposed to the proposed measures.
Green and secularist activists have joined civil libertarians and the Bar Association in calling for the regulations to be scrapped immediately.
Additional thanks to Doug Hynd