Last month's Christchurch quake damage forced tournament organisers to revise match schedules, with three of its five pool matches going to South Island centres: Dunedin, Invercargill and Nelson.
Organisers have confirmed Dunedin's Forsyth Barr Stadium - which during the tournament will be referred to as Otago Stadium - is the venue for four weekend matches.
England will play in three of those matches, including its opening game against Argentina. Carisbrook will be used as a training ground for teams.
Rugby New Zealand 2011 chief executive Martin Snedden said the three South Island cities were logical choices to host an additional match, "but there were always going to be significant problems going beyond that".
"Although it was considered, we came to the view that Dunedin could not have reasonably hosted the Australia v Italy match the day after hosting its first major match, England v Argentina."
Dunedin was the "best bet" to host any formerly Christchurch games, and it was hoped the 25,000 fans who had secured tickets to the England v Argentina match would travel south for the game, he said.
Concern over how the untested stadium and playing surface would perform if given back-to-back matches, coupled with "severe pressure" on accommodation providers forced the double-header to be ruled out, he said.
Dunedin would be "under strain, without doubt", Mr Snedden said.
"But I think it will find a way to cope."
Operational matters have also forced the Scotland v Georgia match to be moved from Dunedin to Invercargill, with the England v Georgia match also considered for a move but later rejected.
Mr Snedden said Dunedin's stadium was "something we were keeping a real close eye on", but as the days progressed it was clear it would be finished on time.
The stadium - hosting one the of the biggest pool matches, England v Argentina - would generate huge media interest.
"It is a brilliant opportunity for the stadium, city, tournament and New Zealand."
He acknowledged the stadium was a controversial decision for the city, but praised those behind the project: "If you build something special you will get people to come."
Dunedin Mayor Dave Cull said while the city's gain was tempered by Christchurch's loss, it was comforting Dunedin would host many of those fans affected by the February 22 earthquake.
"They know they're always assured of a very warm welcome here."
He was confident the wider region would be able to accommodate fans, with each match expected to add about $5 million to the economy. Tourism Dunedin chief executive Hamish Saxton said the announcement was "terrific news for Dunedin and the Southern region".
Otago and Southland would become a "second home" for big-spending England fans, who were predicted to pump millions into the economy.
The city's accommodation sector was expected to be full during big games, with camping grounds in Dunedin capable of hosting about 500 campervans.
Earlier this year, Dunedin Venues Ltd chief executive David Davies said three World Cup matches were likely to cost $400,000.
However, following the announcement of the extra pool game and ongoing talks with contractors that figure was likely to be "half of what was previously reported", he said yesterday.
Asked for comment about gaining the extra pool match, Mr Davies was succinct: "Yippee."
