Police have arrested two men for an alleged primary school break-in and theft in Pooraka overnight.

At about 12.05, Police Security Services responded to multiple alarm activations at the Pooraka Primary School, corner of Scott Street and South Terrace.

On attendance, security saw two young men running up a street adjacent to the school.

Police attended and set up cordons in the hope the suspects were still in the vicinity.

With the assistance of the police dog, a 20-year-old man from Pooraka was found hiding up a tree in the back yard of a home on South Terrace.

The search continued for a second suspect who was found minutes later in the back yard of another South Terrace home.

A computer belonging to the school was also found dumped in a nearby street.

Both men have been charged with aggravated serious criminal trespass and theft.

The 20-year-old man was further charged with breaching bail and carrying an offensive weapon.

He was refused police bail and will appear in the Holden Hill Magistrates Court today.

The second suspect, a 19-year-old Pooraka man was released on bail to appear in the same court on 13 September 2011.

There are three more days until the majority of students return to school from holidays.

Police ask the public, especially those living in the vicinity of schools, to report any suspicious persons, activity or behaviour in or around school grounds to immediately phone the Police Assistance Line on 131 444.

Anyone with information about the overnight incident is asked to contact BankSA Crime Stoppers on 1800 333 000.