The campaign will urge festival artists and audiences to text in their names in order to generate an automatic petition to free U Win Tin, a 75-year-old journalist jailed in Myanmar (formerly known as Burma).
U Win Tin was secretary of the country's democratic opposition until 1989, when he was imprisoned by the military regime.
Rosemary Burnett, programme director for Amnesty International Scotland, said: "Twice this year the Myanmar authorities have put U Win Tin's name on the list of people to be released, but did not actually free him. Now is a crucial time to apply extra pressure to release him immediately and unconditionally."
Although this is the third year running that Amnesty has petitioned for Myanmar's longest-serving prisoner of conscience, it has used only online and traditional petitions so far.
Rachel Lucien, marketing manager for Amnesty International, said she hoped the method would attract younger signatories this year: "This is a new mechanism that is easy to use. We're hoping to attract people who wouldn't normally stop to sign a petition for someone with a clipboard."
She said that because this was the first such campaign Amnesty had run it was hard to predict how many additional names it would collect. But she added that the initiative was more about getting young people involved than large numbers. Once collated, the names will be added to a hard copy petition.
The technology is being supplied by TXT4Ltd, a London-based technology company that already lists Christian Aid and Oxfam among its clients.
Key phrases such as Freedom6 are being mentioned in live performance acts and advertised on an Amnesty-branded pink taxi, the festival programme, posters and flyers. Texters need to send their full name to 64118 to take part. Amnesty will use the keywords to track the success of each communication channel.
Lucien said this would help in planning for future campaigns.