Indonesians dumped over 1,200 pairs of sandals, flip-flops and slippers at collection points across the country in support of a teenage boy who was convicted of stealing Wednesday.

The 15-year-old, who cannot be named for legal reasons, was found guilty for stealing a police officer's sandals, a district court in Central Sulawesi province said in a ruling late Wednesday.

The boy could have received five years in prison, but was sent back to his parents for counselling.

"Based on evidence and witness testimonies, we found him guilty legally and convincingly of committing a theft," judge Rommel Tampubolon told Palu district court.

"But considering his age, we decided to send him back to his parents," he said in a ruling late Wednesday.

The boy claimed he was beaten by police. In a country where official corruption is rife and theft of millions in public funds is often punished with just a slap on the wrist, the case has turned into a cause celebre.

"This action of solidarity by the public shows that they disagree with the criminalisation of juveniles, that it goes against a sense of justice," Arist Merdeka Sirait, chairman of Indonesia's Child Protection Commission, told AFP.

"This is only a case because the stolen flip-flops happened to belong to a police officer. That is arrogant and we hope it stops here."

Police in the city of Palu, including one who said he owned the stolen sandals, caught the boy and badly beat him and two of his friends in the street, demanding the footwear be replaced.

"The policemen slapped and beat us. I fell into a ditch and got bruises on my face and legs," the boy told AFP.

"I did not mean to steal. The sandals were left on the street outside the policeman's front yard."

The theft took place in November 2010 but has turned into a protest movement in recent days because of the court action.

People have also been hurling footwear at the police station in Palu.

"We will send the collected footwear to the national police headquarters to replace the stolen ones," National Commission for Child Protection spokesman Naswardi said.

Police said they had jailed one of the officers who beat the boys for 21 days and stripped him of an upcoming promotion.

Children can be jailed in Indonesia alongside adults, but child protection laws state that imprisonment should be a "last resort".