Cameroon's team manager Andre Nguidgol has said that the absence of Roy Keane could work against the African champions.
Nguidgol said Cameroon are certainly taking nothing for granted despite the Republic of Ireland losing their inspirational skipper.
Team manager Andre Nguidgol said: "Some people think this is a very big advantage for Cameroon but we don't agree.
"A team is a team. It's 11 players, not one player. Ireland will come up with a strategy and will no doubt play even harder now that Keane is not with them.
"We have to be careful and prepare ourselves. Even without Keane, it's still the World Cup and Ireland are still one of the best sides."
Cameroon's preparations hardly got off to the best of starts - a row over bonuses and flight problems meant they were five days late arriving in Japan.
But they are making up for lost time at their Nakatsue training camp near Oita and German coach Winfried Schaefer has no injuries to contend with.
PA