The parents of jailed Australian reporter Peter Greste are worried public interest in their son’s case will flag as Egypt’s court process drags on.

The parents of jailed Australian journalist Peter Greste fear public interest about their son’s plight could wane before he makes his way through Egypt’s justice system.

Greste will spend at least another week in a Cairo prison after being denied bail during his third hearing overnight.

The Al-Jazeera journalist and two colleagues have been detained for almost three months after being accused of spreading false news and supporting the blacklisted Muslim Brotherhood.

Greste’s father Juris Greste says he was expecting a “celebration of sorts” after the latest court appearance, in which his son was allowed an interpreter for the first time.

But Juris Greste says he now fears public interest in the case, which he and wife Lois have credited for keeping their son safe, could begin to fade if the case drags on.

“We regret we are not able to offer you more,” he told reporters in Brisbane on Tuesday.

“We need your continued interest … (but) the longer it draws out without any turns or any developments, the harder it is for us to maintain your interest.”

Mrs Greste said she expected the Egyptian government would push the charges through the courts, even with a lack of evidence, to save face, meaning there could be no near end in sight for her son.

“Once it went into the judicial system, we knew that it had to take its course,” she said.

“But I think they have got themselves into a corner, which is very difficult to get out of and they need to find a way of getting out of this comfortably for them.”

In the latest hearing, police witnesses were questioned about the journalists’ arrests in a Cairo hotel in late December and the evidence they have against the trio.

Most refused to provide details of evidence, but said they stood by their original statements.

During a court recess, Greste told reporters that the prosecution case was without foundation.

“We haven’t seen any evidence in the court that possibly justify the charges of our imprisonment,” he said.

“We spent three months in prison on baseless charges.”

The trial resumes on May 31.