More than 13,000 people are expected to take part in the "Golden Oldies" sporting competition in Christchurch in March 2018.
The tournament, for people aged over 35, will cover 10 sports including rugby, netball, softball, basketball and lawn bowls.
Festival director Peter McDermott said more than 9000 competitors would be joined by more than 4000 supporters and officials.
It would be the most competitors ever in an event held in the city, he said.
Mr McDermott said between 80 and 85 percent of those would be from overseas.
About 30 percent of those from overseas will be from Australia, with strong showings also from the United States, Canada, Japan and Argentina.
Mr McDermott said most visitors would be in Christchurch for at least a week.
The visitors were expected to inject $33 million of direct economic benefit to the Canterbury region.
Mr McDermott said he was confident Christchurch would be ready to host the visitors in 2018.
"We were confident two or three years ago. We were assured by CERA [Canterbury Earthquake Recovery Authority] and the council that they were making good progress. We have all the fields we need, and all the hotels contracted that we need.
"By the time 2018 comes around I think it will be a great place to be."
The festival was set to run from 31 March to 29 April 2018.