Members of the Auckland branch of the National Committee for Tonga's Democracy Movement have launched a fresh protest against the royal family.
The demonstrators are again outside King Taufa' ahau Tupou IV's residence in Epsom after holding rallies earlier this year.
The group's communications officer Josh Liava'a says new information suggests the royal family is the richest in the world.
"We have uncovered a lot of corruption, dishonesty, embezzlement which have been committed by the king, his family and top people in government and we are talking of about 300 billion US dollars that these guys are hiding."
The King is currently in New Zealand for medical treatment.
The movement's claim makes the King the world's wealthiest individual.