An Adelaide pedophile who sexually abused two young brothers will spend the next week behind bars, as his victims ramp up opposition to a home detention sentence.

Vivian Frederick Deboo, 74, faced the South Australian District Court on Wednesday after pleading guilty to multiple counts of indecent assault and gross indecency against the pair in the 1990s.

The brothers cheered outside court after Judge Simon Stretton revoked Deboo's bail, but a sentence will not be handed down until next week.

Deboo served two years in the mid-1990s for the sexual abuse of three other boys, but the brothers, who knew Deboo through their Baptist church, did not come forward until 2015.

Outside court, the pair and supporters gathered with placards and chanted "shame on you, Viv Deboo" as he arrived in a taxi.

A spokesman, who wore a mask and stood alongside the brothers, said a home detention sentence would not be a fair punishment.

"The community would say that they expect harsh penalties, not only to deter that particular individual but deter anyone that would consider perpetrating such actions on our young people," he said.

With the court's gallery full, Judge Stretton allowed supporters of the brothers - many wearing t-shirts protesting Deboo's home detention - to sit in the jury box.

Joana Fuller, for Deboo, argued a report finding him an unsuitable candidate for home detention was invalid because of inconsistencies.

But prosecutor Peter Salu said Deboo showed no remorse for his actions and called for an immediate jail sentence.

"The prisoner has relied on his size and his age and his family connections, he's forced himself onto these victims," he said.

Dr Salu said the court could not find that Deboo no longer posed a risk to the community, and his age should not deter Judge Stretton from jailing him.

Judge Stretton said Deboo's suitability for home detention was only one consideration in sentencing, and other factors included the need for adequate punishment.

Concerns Deboo may be sentenced to home detention moved the state opposition to this month introduce legislation to the South Australian parliament that would ensure he be jailed.

Labor's proposals would ban convicted pedophiles from serving jail terms at home.