Barbra Streisand's concert in Rome next month should be cancelled because of excessively high ticket prices, consumer groups in Italy have said.
Barbra Streisand is embarking on a month-long tour of Europe
The Adusbef and Codacons groups urged the city and the Italian Olympic Committee to deny Streisand use of the Stadio Flaminio on 15 June.
Prices, ranging from 150 euros (£100) to more than 900 euros (£600), were "absurd and shameful", the groups said.
Streisand's Rome concert will kick off her European tour.
The 24,000-seat stadium "is public property and cannot be used for immoral deals that are shameful to a civilized country", Adusbef and Codacons said.
All but the cheapest tickets are still available to buy on the internet, the Reuters news agency reported.
Organisers of the concert were not immediately available for comment.
Streisand's 2006 US tour was ranked the second-highest grossing tour in the US last year, generating $92.5m (£46.8m), with the average ticket costing $298 (£151).
The Rolling Stones tour ranked first.
Streisand will be accompanied by a 58-piece orchestra on her month-long European tour, which includes concerts in Austria, France, Ireland and the UK.
Tickets for her first date at London's O2 arena - formerly the Millennium Dome - sold out in just 20 minutes, despite tickets costing between £100 and £600.