MIAMI (AFP) - A Florida judge has deemed unconstitutional a law banning baggy pants that show off the wearer's underwear, local media reported Tuesday.

A 17-year-old spent a night in jail last week after police arrested him for wearing low pants in Riviera Beach, southeast Florida.

The law banning so-called "saggy pants" was approved by city voters in March after supporters of the bill collected nearly 5,000 signatures to put the measure on the ballot.

The teen would have received a 150 dollars fine or community service, but he spent the night in jail due to a history of marijuana use, the Palm Beach Post newspaper said.

"Somebody help me," said Palm Beach Circuit Judge Paul Moyle, before giving his decision.

"We're not talking about exposure of buttocks. No! We're talking about someone who has on pants whose underwear are apparently visible to a police officer who then makes an arrest and the basis is he's then held overnight, no bond."

"Your honor, we now have the fashion police," added public defender Carol Bickerstaff, who asked the law be declared "unconstitutional."

The judge agreed with Bickerstaff immediately, reported the Post.

Laws that ban low-slung pants are on the books in several US cities, including Delcambre, Louisiana, where offenders can be fined up to 500 dollars or jailed for up to six months.

Dallas, Texas and Atlanta, Georgia are among the larger US cities considering similar measures.