Amid an uproar over the huge demand for seats to pop idol Hannah Montana's tour, a U.S. federal judge on Monday barred the use of automated software to make mass ticket purchases from the leading box-office service Ticketmaster.

U.S. District Court Judge Audrey Collins issued a preliminary injunction against Pittsburgh-based software maker RMG Technologies, whose computer programs, Ticketmaster says, have enabled scalpers to gain rapid, repeated access to its online retail system.

The court order stems from a lawsuit brought against RMG by Ticketmaster, a unit of IAC/InterActiveCorp, in April, before tickets for the 54-date Hannah Montana concert tour went on sale.

But abuse of the popular ticket retailing system by brokers and resellers has grown more and more brazen since then, said Joe Freeman, a lawyer for Ticketmaster.

Ticketmaster says RMG software enables digital scalpers to breach its Internet box-office system and electronically cut in line ahead of regular human customers to scoop up large numbers of tickets that can then be resold at highly inflated prices.

They're cheating consumers out of a fair shot at these tickets, and we're not going to stand for it anymore, Freeman said.

The practice has come under investigation by the attorneys general of at least three states -- Missouri, Arkansas and Pennsylvania -- who are looking into whether ticket resellers are violating state consumer protection laws.

State authorities were reacting in large part to a public outcry over crushing demand for seats to the upcoming Hannah Montana tour -- and soaring markups of those seats as they showed up for sale in the secondary ticket market on Web sites like Ticketliquidator.com, StubHub.com and Gotickets.com.

Hannah Montana is the TV alter ego of 14-year-old Miley Cyrus, daughter of country singer Billy Ray Cyrus. She plays a teenager living a double life as a young rock star on the hit Disney Channel cable show.

Her TV character has released two top-selling albums during the past year.

Her Best of Both Worlds Tour, which opens October 18 in St. Louis, has become the hottest show of the year, with average ticket prices rising to $237 earlier this month, exceeding the going rate for adult acts such as the Police, Bruce Springsteen and Van Halen. Scalpers and brokers were reported to be seeking as much as $2,500 to $3,000 for a Hannah Montana ticket.

The starting face value of those tickets for two Los Angeles-area shows ranged from $26 to $66 a seat, according to Ticketmaster.

Neither RMG executives nor its attorneys were immediately available for comment on the judge's ruling.

But a spokesman for San Francisco-based StubHub, a unit of online auctioneer eBay Inc., has said that insatiable demand, not unscrupulous behavior, was driving up prices on the resale market.

Judge Collins' order bars RMG from creating, trafficking in, facilitating the use of or using computer programs or other automatic devices to circumvent the copy protection system on Ticketmaster's Web site.

It also prohibits RMG from using information gained from the Ticketmaster site to create computer programs designed to evade its copy protection and regulation systems.

Pennsylvania