Two South Australian Government carers have already failed strict new psychological testing for child protection staff.

The new tests involve face-to-face interviews with psychologists, set up in the wake of the Child Protection Systems Royal Commission last year.

The investigation probed weaknesses in the state's child protection systems exposed by the crimes of paedophile carer Shannon McCoole, who was sentenced in 2015 to up to 35 years in jail.

But the Public Service Association (PSA) says the new psychological tests expose workers to personal and intrusive questions, and are “irrelevant” and “intrusive”.

Reports say new job applicants are now required to discuss their sexual experiences, fantasies and use of dating websites, among other activities.

Premier Jay Weatherill says the tests are essential for child protection.

“It is sad that we have to have this level of intrusion and scrutiny, but the truth is that we've already seen in the past that some people will try and infiltrate their way into these roles so that they can get access to children,” he said.

The Child Protection Department has tested 227 of its 350 carers so far, with two being found unsuitable.

One of the two employees has gone on extended leave, while the other is now in an administration role, the department said.