The Trustees of the Ashika Relief Fund, set up by the Tongan government to raise money for the survivors and families of victims of the ferry disaster, had received nearly half a million US dollars as at the beginning of this week.
74 people lost their lives when the vessel sank last month.
A statement from the Prime Minister's Office says the nine trustees, made up of six senior church officials and three government appointees, report that contributions are continuing to come in from around the world.
But they say more financial help is needed.
The trustees say it would be more useful for the Ashika Fund money to be used for rehabilitation and longer term needs, with other funds stepping in to provide more immediate needs.