The two Tunisians, Noureddine Taboubi and Abdelkrim Jrad, planned to take part in a congress of Bahraini trade unions but were denied entry yesterday, the Tunisian General Labour Union (UGTT) said.
Sami Tahri, the UGTT spokesman, told Mosaique FM radio that the two were banned "because of the UGTT's rejection of Hezbollah's classification as a terrorist organisation".
The ban was "undemocratic" and "contrary to international law", he said, adding that "there are always countries which are against any free and independent positions".
The move by the six-nation Gulf Cooperation Council (GCC), led by Saudi Arabia, formed part of "an offensive by foreign and other regional forces to divide the Arab world and destroy its forces", the UGTT said.
The head of the Tunisian Order of Lawyers, also a member of the Nobel quartet, called on all "forces in Tunisia and in the Arab world to exert pressure on governments to reconsider their decision".