Baseball, surfing, skateboarding, climbing and karate are in, while squash, bowling and wushu are out for the Tokyo 2020 Olympics.

The decision will mean that 33 sports will be contested in Tokyo, up from the 28 being decided in the Rio games.

“This is really a milestone in the innovation of the Olympic programme which we can then experience in four years from now in Tokyo 2020,” IOC president Thomas Bach told delegates in Rio de Janeiro.

Japanese baseball star Ichiro Suzuki who plays with the Miami Marlins in the MLB. Photo: AAP

The five extra sports — with women-only softball bracketed with baseball — make up 18 events and 474 athletes in the Tokyo roster.

IOC members voted 85-0 in favour of baseball, but not before some delegates raised concerns about the sport, whose US-based stars are not confirmed for the games.

“At this moment we are not sure that in the days of the baseball competition in Tokyo … that the athletes playing in the United States can take part,” said Franco Carraro, chairman of the working group which oversaw the proposal.

“We hope that the international federation reach an agreement with the United States professional league, as happened with basketball and ice hockey.

Wednesday’s decision ends a more than year-long process which whittled down 26 applications and dropped squash, bowling and wushu — a Chinese martial art from an earlier shortlist.

Baseball is the number one sport in Japan which has produced a raft of stars, and is expected to boost ticket sales by about $US50 million ($A66 million).

The IOC scrapped a short-lived cap of 28 Olympic sports to include the new events,with golf and rugby returning to the Olympic progamme in Rio after a gap of 112 years and 92 years respectively.