Dec 30 (Reuters) - UEFA president Aleksander Ceferin has reiterated his opposition to FIFA"s plans to stage a biennial World Cup, saying the women"s tournament or the Olympics would be affected if they were held in the same year as the finals. The European soccer governing body and its South American counterpart CONMEBOL have strongly opposed the idea which FIFA president Gianni Infantino has said would create an extra $4.4 billion in revenues for the world soccer organisation. "Europe and South America are against (the plan) and those are the only (continents with) World Cup winners in history. The problem is that the World Cup has to be every four years to be interesting," Ceferin said at the Expo 2020 Dubai fair. "Second, if it would be every two years, it would cannibalise women"s football because it would be at the same year as the women"s football (World Cup), other sports, the Olympic Games - many mistakes. "It"s simply a bad idea and it will not happen because it is a bad idea, not because we are opposing it." FIFA"s plans had the International Olympic Committee (IOC) worried with attendees at a summit earlier this month voicing "serious concerns" over the proposals and its impact on the world sporting calendar. "Why are the Olympic Games every four years? Because it"s an event that you have to look forward (to), that you have to wait (for), and you have to enjoy it," Ceferin added. "And it"s the biggest football event -- it has to be every four years. But it"s very clear - 75% of fans around the world reject the idea (of a biennial World Cup)."