The 1967 constitution of Tonga states that “All men are free to practise their religion and to worship God as they may deem fit in accordance with the dictates of their conscience and to assembly for religious services in such places as they may appoint. But it shall not be lawful to use this freedom to commit evil and licentious acts or under the name of worship to do shat is contrary to the law and peace of the land.” It is illegal for any person to practice a profession or trade or to conduct any commercial undertaking on the Sabbath Day unless permitted by law. Agreements made or witnessed on that day shall be null and void. ministers are exempt from serving on juries.
2003 U.S. State Department International Religious Freedom Report on Tonga
Search Amazon.com for books on religious freedom in Tonga