The guerrillas, who have observed a truce with government forces since February 2002, are fighting for a homeland called Eelam for Sri Lanka's 2.5 million Tamil minority.
"The national anthem should symbolise the history of our struggle and victories," Tamilnet quoted the LTTE as saying.
It said the anthem should have a maximum of 18 stanzas in "immaculate Tamil."
The lyrics should extol the "virtues of those who sacrificed their lives in the Tamil struggle, celebrate the unique qualities of exclusiveness and resourcefulness of the Tamil homeland, and manifest the resoluteness, dedication and the aspirations of the Tamil people for freedom and dignity."
In April last year, the LTTE adopted the Gloriosa Lily as their national flower. Ingesting the vine or the flower, commonly known as glory lily, is poisonous, and its roots are used to commit suicide.
The LTTE is known for trademark suicide bombers, and combatants wear a cyanide capsule to avoid being taken alive by government forces.
The Tigers have admitted losing over 18,000 fighters since the first rebel was shot dead by security forces in 1982. A total of over 60,000 people have died in the conflict.