Tom Parker is wanted by the police for pooing in a bag.

The Wanted's chances of success in the US may have gone down the toilet after cops revealed the singer was spotted defecating in a plastic bag and throwing it onto the highway earlier this year.

The shameless Brit could be slapped with a $500 fine and stopped from re-entering the country by authorities the next time the band head across the Atlantic.

One of Colorado State's bylaws reads: "Littering is a class 2 petty offence punishable, upon conviction, by a mandatory fine of not less than $500 upon a first conviction."

Tom's bandmate Jay McGuiness joked to the Daily Mirror newspaper: "I am going to try to avoid Colorado right now, but if we do go, Tom needs to get $500 ready. That was the most expensive passing of a number two [Tom] will ever have."

Siva Kaneswaran chimed in: "It wasn't my s**t out the window ... Tom, it was his log."

The 24-year-old star - who left the country the next day - apparently couldn't wait to relieve himself, despite their tour bus driver telling Tom and his bandmates to wait until they pulled over before going to the toilet.

The boy band are also in trouble with the law in their native UK after it was claimed they threw champagne over a poet and verbally abused him from their hotel balcony in a London hotel.

Dr Todd Smith said: "Suddenly I was hit with a lot of liquid ... There were three young guys laughing at me. One of them said, 'P**s and beer, mate.' "