As of Thursday, only about 400 of 5000 tickets were unsold and committee member Evan Penniall said he expected the remainder to go soon.
The annual festival, the biggest event on the Bluff calendar, will be held on Saturday, May 21 and the gates will open at 10.30am.
Even though food stalls and entertainment ran all day, there were always some people who arrived early and left early, Mr Penniall said.
"As people leave we can let more in. There might be queues at the gate, but we can't do anything about that.''
Among the crowd will be 180 people on a day trip from Auckland.
Their flight lands in Invercargill about 10.15am, and passengers will travel by bus to Bluff, before flying out again at 6.15pm.
Mr Penniall said it was the second time Air New Zealand had put on a flight and he hoped it would become a regular event.
The first flight was about five years ago.
A charter flight from the Chatham Islands carrying 42 people is also expected.
Two years ago the festival committee bought the vacant Club Hotel on Bluff's main street and developed a permanent festival site behind it.
It has covered stages and several sheds for food stalls set around a central courtyard.
Mr Penniall said the site operated very successfully last year.
Being the first festival at the new venue the day attracted significant media attention, which he said had probably helped to spark ticket sales this year.
However, festival organisers never seem to have any difficulty attracting a crowd.
Asked why, Mr Penniall said the day was "good value for money - and there are oysters''.
The food is always a drawcard.
This year's menu includes fresh kina, paua patties, marinated fish, scallop kebabs, salmon, whitebait patties, muttonbirds, crayfish, custard squares and chocolate bites as well as oysters - raw, battered, barbecued with garlic butter and citrus peel, in soup and served as a shot.
Four bands will perform during the day.
The popular oyster-opening and oyster-eating competitions will begin at 12.30pm.
Mr Penniall said the forecast for the day was looking promising apart from "a little rain''.
"All we wish is for the right [weather]. We know we have the crowd.''
