Sydney, Australia - Lawyers in Australia say that police powers introduced for a major gathering of young Roman Catholics later this month will undermine free speech.
Under the powers, police will be able to arrest and fine people for "causing annoyance or inconvenience" to participants in World Youth Day.
Lawyers say this means acts of peaceful protest at the event in Sydney could potentially be deemed a crime.
Police say the powers are needed to organise security for the event.
As many as half a million Catholic pilgrims are expected to join in the five-day meeting in mid-July.
Pope Benedict XVI will also attend, on his first visit to Australia.
'Unnecessary'
Under the new rules, police can fine people A$5,000 ($4,800, £2,400) for annoying or inconveniencing those attending the gathering.
The regulations will apply to 40 locations in Sydney, including parks and stations.
President of the New South Wales Bar Association Anna Katzmann said it was hard to understand the rationale behind the move.
"To make something that causes inconvenience to people the basis for a criminal offence is both unnecessary and repugnant," she said in a statement.
Under the rules, refusing to remove a T-shirt saying "World Youth Day is a waste of public money" could be deemed a criminal offence, she said.
One group, the NoToPope Coalition, says it plans to distribute condoms to highlight its opposition to the Church's stance on contraception, homosexuality and abortion - a protest that could also contravene the regulations.
But State Premier Morris Iemma defended the rules.
"People have the right to protest, they can do so, they can do so peacefully and lawfully," he said.
Police Commissioner Andrew Scipione, meanwhile, said the powers were similar to those police had at major sporting events.
World Youth Day runs from 15-20 July.