Security officials carried out raids in Sydney in 2005 following tip-offs
Five men convicted of a terrorist conspiracy in the Australian city of Sydney have been handed jail sentences of between 23 and 28 years.
The men were found guilty last year of charges such as possessing bomb-making instructions and explosives chemicals.
Prosecutors said they were plotting violent jihadist attacks in protest at Australia's involvement in Iraq and Afghanistan.
The men cannot be named for legal reasons.
The exact details of the plot and the men's intended targets have never been specified, but their trial was the longest in Australian history.
Justice Anthony Whealy of the New South Wales Supreme Court, who passed sentence, said they had been motivated by "intolerant, inflexible religious conviction".
They had shown contempt for the Australian government, its leaders and laws, he said.
Some of the men were reported to have smiled in court as the sentences were handed down.
The arrests in 2005 followed tip offs from hardware store and gun shop owners.
Their suspicions had been raised when the men started to order unusually high amounts of chemicals and guns.
Prosecutors said one defendant had attended a training camp in Pakistan of the Lashkar-e-Taiba group and had set up a paramilitary style camp in rural New South Wales to train three of the other men.
When police raided the men's homes, they found "large quantities of literature which supported indiscriminate killing, mass murder and martyrdom in pursuit of violent jihad", said prosecutor Richard Maidment.
The trial, carried out in a purpose-built courthouse, heard there was overwhelming evidence the men wanted to create "at the very least, serious damage to property" and posed a "serious risk" to the public.
Justice Whealy said the men had on occasions been "inept and clumsy" but that this "did not make their conspiracy any the less dangerous".
"There is no reason to doubt that, absent the intervention of the authorities, the plan would have come to fruition in early 2006 or thereabouts," he said.
But the sister of one of the men said the sentences were too long.
"Not even murderers get sentenced that much," the AFP news agency quoted the unnamed woman as saying.
"Twenty-three years, that's half of his life. It's not fair to him, our community or our religion."
Australia is a close ally of the United States. It was among the first to commit troops to US-led campaigns in Afghanistan and Iraq.
It has not suffered a major peacetime attack on home soil, but 95 Australians have been killed in militant bombings in neighbouring Indonesia since 2001.