KUALA LUMPUR (Reuters) - There will be no revealing costumes at U.S. singer Gwen Stefani's concert in Malaysia this month, a newspaper said on Saturday, after a Muslim student group demanded that the event be cancelled as being too obscene.

Although Malaysia is a moderate Muslim country with sizeable non-Muslim minorities, conservative groups often frown upon departures from strict Koranic injunctions.

Malaysian mobile phone firm Maxis Communications, which is promoting the August 21 show as part of Stefani's "Sweet Escape" tour, promised it would feature no revealing costumes, the Star newspaper said.

"She will abide by the Malaysian authorities' guidelines to ensure that her show will not be offensive to local sensibilities," it quoted a Maxis statement as saying.

Malaysia's official guide for performers says women must be covered from the top of the bosom to the knees, the Star said.

Jumping, shouting and the throwing of objects are barred, while performers may not hug, kiss or wear clothes with obscene or drug-related pictures or slogans, it added.

On Tuesday, an official of the 10,000-strong National Union of Malaysian Muslim Students said Stefani's video promotion clips were obscene and the event would clash with local Asian and Islamic values.

"We want the organizers to cancel the concert, failing which we will ask the authorities to intervene," said Mohamad Hilmi Ramli, the group's president.

Ethnic Malays, who are by definition Muslims, make up just over half of Malaysia's 26 million people, while ethnic Chinese and Indians, who are mostly Buddhists, Christians or Hindus, account for most of the rest.