It is a case about a band, in Bali, with a pedigree problem. Two musicians are standing trial in Denpasar District Court after singing a crowd favourite at a charity concert that likened police to dogs.

The musicians have been charged with "deliberately insulting a state institution in public".

Police, insulted by the song called Anjing, charged the men after they performed at the concert in Bali last July, which was held to raise money after the Yogyakarta earthquake killed thousands of people.

"I thought he is a thug, it turned out he's a police, dog!", the band, Ed, Eddy and Residivis, allegedly sang to a large crowd in Denpasar on July 1. Calling someone a dog, or anjing, is a major insult in Indonesia.

Prosecutors asked judges hearing the case in Bali to sentence guitarist Sofian Hadi and singer Teguh Setia Budi to two years' probation.

"The witnesses testified that the defendants sang a song 'Anjing' in front of the public, and the defendants even asked the audience to sing along with him by beckoning to the microphone," prosecutor Ridwan Kadir said.

Kadir said the deed insulted both the policemen and the institution. The maximum penalty they could face is one and a half years in jail.

Outside the court, Hadi, the song's writer, said the lyrics were meant to portray prejudice in society, in which merely looking at someone could spark fights.

"In this story we took an example where one person was involved in a fight with someone who turned out to be a undercover policeman," he said.

The prosecutor's sentence demand took the band members by surprise. "This just doesn't make sense," Hadi said.

"People can translate a story into different angles. If they are offended, they can simply talk to us. They don't have to criminalise us."

The band started playing in 2005 and Anjing was an audience favorite. However, the band said it had stopped singing the song since July, awaiting the outcome of the court case. The trial will resume in two weeks to hear from the defence team.