Cameroon scored just eight goals in six games as they finished top of their group in the second round of World Cup qualifying, the second lowest of all teams to advance to the final phase in the Confederation of African Football section.
Fellow World Cup participants Ghana (18), Ivory Coast (15) and Algeria (13) all enjoyed great success up front, with only Nigeria (seven) scoring fewer goals.
Cameroon did manage to score four goals in two play-off games against Tunisia to reach the World Cup, while they netted three in their last two international friendlies with Germany and Paraguay.
But midfielder Mbia admits Volker Finke's men have to be 'efficient' up front if they are to progress from Group A, which includes host nation Brazil, Croatia and Mexico.
"It is true that we did not score often, except in the return match against Tunisia (when Cameroon won the home leg of the third round qualifier 4-1 to advance to the finals)," said Mbia, who won the UEFA Europa League with Sevilla in 2013-14 having arrived on loan from Queens Park Rangers.
"We can still improve in that area, and we have the players to get there. I think it will get better as we work tactically. But in a competition like the World Cup, you have to be efficient.
"It is unlikely that you will get that many chances, so you have to try to take those that you get."
Cameroon, four-time Africa Cup of Nations champions, are set to compete at a seventh World Cup - the most of any African nation.
In those six previous appearances, Cameroon have only progressed past the group stages once - reaching the quarter-finals at the 1990 World Cup in Italy but a good result in their opening game against Mexico on June 13 could put them on track for the knockout rounds.
"It is important not to lose the first game, because it can determine a lot of things," the 28-year-old said.
"Mexico is a very good team, their style reminds me of that of Spain. Technically, they are very strong.
"Then we face Croatia, who have (Ivan) Rakitic and (Luka) Modric. They are one of three teams that will fight for second place in the group.
"Brazil are favourites and it does not bother me when they say they will finish in first place. Brazil is always a favourite, especially if they play at home."
