Wears imprisonment like a badge of honour: Khaled Cheikho.

The biggest terrorist cell in Australian history has been dealt a significant blow with a Sydney court dismissing an appeal by five men to have their convictions and sentences quashed.

But the decisive ruling is unlikely to dent the conviction of the Pendennis cell members, who wear their imprisonment like a "badge of honour", or some of their family members, who continue to maintain their innocence.

In the NSW Court of Criminal Appeal on Friday, Chief Justice Tom Bathurst announced the convictions for convictions for conspiracy to prepare for a terrorist act would stand, as would the maximum sentences ranging from 23 to 28 years.

Mohamed Eli Elomar.

Mohamed Ali Elomar, Abdul Rhakib Hasan, Khaled Cheikho, Moustafa Cheikho and Mohammed Omar Jamal were found guilty by a jury in October 2009 following an 11-month trial in a purpose-built court room at the Sydney West Trial Courts in Parramatta.

The case was circumstantial, as no precise target had been selected, but the jury accepted the Crown's argument that an attack could have been imminent at the time of the men's arrest in November 2005.

The Crown relied on the large amount of extremist Islamic literature, training manuals for the manufacture and detonation of explosive devices and firearms, chemicals and ammunition the men had collected to substantiate the conspiracy.

Mohammed Omar Jamal.

During an appeal hearing in August last year, defence lawyers raised several grounds, including Justice Whealy's decision not to discharge the jury after several jurors reported being followed to their cars. One juror said a female relative of one of the men followed her to the car park and took notes, presumably of her registration number. But the appeal judges said the incidents did not mean the jurors had lost their objectivity.

Defence counsel also took issue with the gruesome images, including beheadings, the jury were shown.  But the appeal judges said the images were relevant and probative and any "discomfort" jurors may have felt was not enough to substantiate unfair prejudice against the men.

They three-judge panel also found the Justice Whealy correctly applied the rules of evidence in admitting evidence that Moustafa Cheikho had attended a militarist Islamic training camp in Pakistan.

In appealing their sentences, defence lawyers said Justice Whealy did not give enough weight to the "cultural isolation" the men would suffer in Goulburn jail's "Supermax" high-security unit.

Hasan's counsel, prominent appeals barrister Tim Game SC, said his client was "isolated and depressed" and estranged from his wife and four children.

But Justices Bathurst, Clifton Hoeben and Caroline Simpson said Justice Whealy had adequately taken the issue into account. They also said he made no error in finding there was little prospect of rehabilitation or de-radicalisation for most members. In remarks handed down in February 2010, Justice Whealy said many of them "wear their imprisonment like some kind of badge of honour", seeing it as "a test of their faith and a burden willingly borne as a duty arising from their fundamentalist religious conviction".

One of the cell members, Khaled Sharrouf, was released in 2009 after serving his four-year sentence and left Australia last year with his wife and four children to join Islamic State in Syria.