All would be revealed in four to six weeks, chairman John Edminstin said.
''All the money the festival makes will go back to the community - every cent. We are going to announce something which will benefit Bluff big time.''
Rumours are circulating the money will be used to buy a building as a base for the popular festival, or possibly a community centre.
Mr Edminstin would not be drawn on that, saying only the money would be spent on ''a major project''.
He said this year's festival was another ''roaring success'', although he would not reveal the surplus figure, other than to say it was on a par with previous years.
The trust had more than $333,000 in the bank after last year's festival so its bank balance could now be close to $400,000.
The present trust was set up six years ago after earlier festival planning went pear-shaped.
In the early years, the festival was run by a Bluff-based committee, but when the festival and the time and effort needed to organise it began to grow, that group sought help from the Invercargill City Council.
Problems including low attendances, the arrival one year of a ship carrying a leaking container of toxic chemicals, unexpected storms, and an unsuccessful attempt to hold the festival in Invercargill instead of Bluff meant the festival was in danger of dying.
Mr Edminstin said the present committee had been formed with the aims of trying to make the festival work, to bring visitors to the town, to provide an avenue where local groups could do their own fundraising by operating food or craft stalls, and to save up enough money from festival surpluses to do something significant for Bluff.
The trust also made annual donations to the local groups which helped at the festival, he said. Those donations were included in the trust's operating expenditure budget and did not come out of festival surpluses.
The festival would not be successful without the hard work of the volunteer committee members and local organisations and it was only fair surpluses be returned to the town, he said.
''When we started we had $10 in the bank, and that was donated by a local lady ... We've done this all on our own without any help from the city council or [tourism organisation] Venture Southland. We've run successful festivals and we've made profits on our tod.
''Now we've managed to build up a fund we can actually do something with ... Perhaps some people are a bit jealous about that.''
