Prime Minister Julia Gillard may have joked her way on Thursday by saying that the student who threw a salami and tomato sandwich at her may have thought she was hungry.

But the teener found out on Friday that the biblical teaching that when someone hits you with bread, not to counter strike by hitting the thrower with stone but with bread also does not apply since his misdemeanour would go not unpunished. News Limited reported that the student of Lyneham High School in Canberra would be suspended from three to five days for what he did.

However, during the week he is suspended, the erring student would still be required to do schoolwork. The suspension was the result of a meeting among the teen, his parents and school authorities.

Even Ms Gillard's critics agree to the punishment for the youthful offender.

"Whether it is Mr (John) Howard in the office of prime minister, or Julia Gillard in the office of prime minister, there is a need for our community to continue to respect the office," said former PM Kevin Rudd who insisted the kid should have eaten the sandwich for his lunch.

"It's just basic respect, whether it is the prime minister or anyone else ... I'd just say to the kids watching, don't be silly, don't be stupid. Come one, be a bit more mature, I find it really repugnant," said Opposition treasury spokesman Joe Hockey.

According to footage of Ms Gillard's visit to the school to explain the federal government's support for the Gonski school education reform, the sandwich thrower was wearing a blue hoodie, which made it possible for the school to identify the erring youth.

A similar incident in the early part of May at Marsden State High School resulted in a 10-day suspension for a student named Kyle Thomas, who denied he throw the sandwich to Ms Gillard.

On the same day of the second sandwich-throwing incident, the Australian Capital Territory joined New South Wales in signing up to the reforms, which boosted funding for ACT schools by $190 million over 5 year. Ms Gillard needs to convince five other Australian states to also ink the school reforms.

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