During the last three Republican national conventions, police officers have arrested hundreds of people as the gatherings have drawn thousands of protesters objecting to the party’s positions on a range of issues, from wars to the economy to the environment.

But this time around, the protesters planning to gather in Tampa the last week in August hope their ranks will be swelled by the Occupy movement, whose members have said that they see the party’s expected nominee, Mitt Romney, as the embodiment of a financial system that favors the rich and corporations over ordinary citizens.

Now, in an effort to control demonstrations and prevent disturbances, officials in Tampa are taking unusual steps that they say will help ensure public safety but that many demonstrators and civil liberties advocates say will place unacceptable limits on public dissent.

In May the city adopted a temporary ordinance that will clamp down on protests in dozens of blocks near the Tampa Convention Center. Among other things, the ordinance requires a permit for groups of 50 or more to gather in parks; sets a limit of 90 minutes on parades; and bans an array of items, including glass bottles, aerosol cans and pieces of rope longer than six feet. It also provided for an official parade route for protesters along with viewing areas.