THE mounting pressure on Education Minister Grace Portolesi and Premier Jay Weatherill over the alleged cover-up of the rape of a primary school student was written all over their faces yesterday.

The pair attended a children's health program launch where they were grilled about an independent inquiry into the rape which occurred in late 2010 but was not revealed to parents for two years.

News of the case broke in late October and Ms Portolesi and Mr Weatherill, who was education minister at the time, have been under growing pressure since.

Yesterday, they arrived at the Mile End event at the same time but in separate ministerial cars, prompting waiting media to split between them and conduct separate press conferences.

Ms Portolesi, in particular, faced heated questioning and ended up walking out while reporters persisted.

Inside, Ms Portolesi and Mr Weatherill - who are close political allies, sat together and, according to a spokesman - discussed questions they had faced.

Later, as they left, the pair held a second, joint press conference outside.

Both will appear before an inquiry into the case - headed by former Supreme Court Justice Bruce Debelle - but neither would say when.

Mr Weatherill was asked to appear "some time ago", while Ms Portolesi said she was approached on Monday night. However, her staff discussed the issue on Friday.

Mr Weatherill said he did not know if ministerial staffers such as his chief of staff Simon Blewett or Ms Portolesi's chief of staff Jadynne Harvey - who were both told of the rape in 2010 - had already given evidence to the inquiry.

"I don't know and I wouldn't ask," he said. "Witnesses shouldn't discuss their evidence with each other."

Mr Weatherill said Justice Debelle's final report would be discussed in Cabinet before being publicly released.

The Education Department and SA Police have been tracing the history of the man convicted of the 2010 rape to see if he worked elsewhere with children.

However, Ms Portolesi said yesterday she had "no new information".

An SA Police statement said that the man's employment history was "confidential".