Extraordinary new powers will allow police to arrest and fine people for "causing annoyance" to World Youth Day participants and permit partial strip searches at hundreds of Sydney sites, beginning today.

The laws, which operate until the end of July, have the potential to make a crime of things such as wearing a T-shirt with a message on it, handing out condoms at protests, riding a skateboard or even playing music, critics say.

Police and emergency services volunteers will be able to direct people to cease engaging in conduct that causes annoyance or inconvenience to participants in a World Youth Day event or risk a $5500 fine.

A police source said causing an annoyance or inconvenience was a highly subjective offence. Civil libertarians said the new powers were more extreme than those used during last year's APEC summit and the 2000 Sydney Olympics.

The regulations apply to more than 40 central Sydney locations, including Darling Harbour, the Opera House and the Harbour Bridge. People entering more than 500 schools and 35 train and bus stations will also be subject to vehicle and baggage searches that require them to remove jackets, gloves, shoes and headwear if requested.

The NoToPope Coalition — an alliance of gay pride, pro-contraception and atheist groups — is waiting for police approval for a protest that will feature a same-sex "kiss-in", mardi-gras style costumes and distribution of free condoms. Spokeswoman Rachel Evans said the rally was about delivering a peaceful message that being gay is not a disorder, that contraception is not a sin and that women should enjoy equal rights in the church. Up to 15,000 people are expected at the march.

The march is on Saturday 19th July, 12 noon at Taylor Square, Sydney

Slogans like Pope Go Homo and The Pope Is Wrong - Put a Condom On will be splashed across protesters' T-shirts during next week's World Youth Day.

The NoToPope Coalition held an "annoying fashion parade" outside the New South Wales Parliament yesterday to unveil the shirts they will wear during a Sydney rally on July 19.

They fear police will ban them from wearing the shirts, after state police were given powers to arrest anyone they believe is causing annoyance or inconvenience to pilgrims.

Failure to comply with the laws, introduced for the events in Sydney from July 15-20, can attract a penalty of up to A$5500 ($7050).

Eight police officers watched as about a dozen members of the protest group unveiled their shirts.

Anti-pope activists in Australia have won permission to 'annoy' Catholic pilgrims at the World Youth Day celebrations in Sydney after a court upheld their right to hand out condoms and coat hangers.

The decision, by the Federal Court, strikes down a law introduced by the state of New South Wales that would have fined anyone causing annoyance to the estimated 225,000 pilgrims visiting Sydney to celebrate with Pope Benedict XVI. The fines could have been up to A$5,500 (£2,700).

As soon as the court had given its ruling, Rachel Evans, one of two protesters from the No To Pope Coalition who brought the case, started handing out condoms to pilgrims. We're not seeking to annoy or inconvenience anyone, she said, wearing a T-shirt declaring: The Pope is wrong, put a condom on.

The New South Wales government had claimed that the new regulations extended to police the same rights to suppress trouble as they already had for big sporting events. It emphasised that a ban on causing inconvenience remained in force.

Ms Evans and another student activist, Amber Pike, argued that the law was unconstitutional because it infringed their right to peaceful protest. The judges ruled that the attempt to regulate annoying behaviour would affect freedom of speech because of uncertainty about how it could be defined.

The statement from the judges was very clear, Ms Evans said. We have the right to peaceful assembly and these annoyance laws contravene that right. The judges specifically said condoms, T-shirts, coat hangers and so on.

Protesters are handing out coat hangers as a reference to backstreet abortions — a consequence, they say, of Catholic opposition to contraception and abortion.