Mr Tissainayagam is appealing against a 20-year sentence
A Sri Lankan Tamil has been named foreign journalist of the year at the British Press Awards in London.
JS Tissainayagam was arrested in 2008 and sentenced to 20 years in jail for inciting racial disharmony in his magazine. He was bailed in January.
US President Barack Obama mentioned Mr Tissainagayam last year as an example of reporters jailed for their work.
Mr Tissainayagam denies supporting violence. International human rights groups had campaigned for his release.
The chairman of the British Press Awards judges, Bob Satchwell, told the BBC Sinhala service: "There is obviously concern about journalism in Sri Lanka and some other parts of the world.
"What we hope we will do in highlighting someone's position in this way is perhaps put pressure on governments in whichever country the journalist might reside to get the journalist released.
"What we always try to argue for is freedom of expression, therefore the freedom of the press, and that journalists should not be harassed and maltreated in this way."
Last September, Mr Tissainayagam was given an award for courageous and ethical journalism by the Paris-based group Reporters Without Borders.
On Tuesday, Reporters Without Borders appealed to Sri Lankan President Mahinda Rajapaksa to publicise the results of investigations into the disappearance of another journalist who vanished two months ago.
It notes that senior officials are still implying that Prageeth Eknaligoda staged his own disappearance and alleges that the police have shown "no interest" in finding him alive.
"We urge the president to provide credible information about what happened to him," Reporters Without Borders said.
Media rights groups say Sri Lanka is one of the most dangerous places for journalists to work.
They accuse the authorities of intimidating and harassing journalists critical of the government's policies.
Official figures show that nine journalists have been killed and more than 25 assaulted in the past four years in Sri Lanka.
The government says it has nothing to do with either the killings or the attacks on journalists.