MONTERREY, Sept 17 (Reuters) - A Mexican state legislature has asked the country's federal government to fine singer Miley Cyrus after one of her dancers spanked Cyrus's backside with a Mexican flag as she "twerked" during an independence day performance.

Cyrus, 21, who has grabbed headlines for her admitted drug use, sexually suggestive dancing and wearing as little as a pair of boots in a music video, was performing in Monterrey in the northern state of Nuevo Leon.

Local lawmaker Francisco Trevino said that the Nuevo Leon state legislature had approved a warrant for the Interior Ministry to enforce the law on use of the flag.

She or her team could be fined up to the equivalent of around $1,200 or be detained for 36 hours, Trevino said.

Mexican authorities are often sensitive toward signs of disrespect for national symbols. In 2008, singer Paulina Rubio was fined for posing without clothes but wrapped in the country's flag. (Reporting by Gabriela Lopez; Writing by Christine Murray; Editing by Ken Wills)