Bale scored in the first Liga game of the season at Deportivo La Coruna but has not found the net since and was whistled by Madrid fans on Wednesday during the 3-0 Champions League win over Apoel Nicosia.
"We want and need him to do more on the pitch, and he does too," Zidane told a news conference. "But we are calm because he will do it soon."
Real Madrid face high-flying Real Sociedad at Anoeta on Sunday and, with Cristiano Ronaldo serving the final match of his five-game suspension and Karim Benzema injured, the onus will be on Bale to make the difference.
However, Zidane said the winger does not have to be the team’s leader in the clash against Eusebio Sacristan’s second-placed side, who have won all three of their opening games and are level on nine points at the top with Barcelona.
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"He will do his job," said Zidane. "Each day he feels better. I said that he has had four months out of the team (injured) and to return to his level he needs at least four months.
"We don't have to think that because Cristiano and Karim are not there he has to be the leader, there are other important players too.
"Occasionally a player makes the difference with his goals, his moves, but we make the difference as a group more than an individual player."
Zidane confirmed that Toni Kroos and Jesus Vallejo would miss the game with injury problems in a squad already missing Ronaldo, Benzema and the suspended Marcelo.
Eight-placed Madrid are already four points behind Barca and if the Catalans win at Getafe on Saturday there will be a seven-point gap before the kick-off at Anoeta on Sunday, increasing the pressure on Bale.
"If (Bale) scores two goals, everyone will be happy and the dynamic of what everyone thinks of Gareth will change," said Zidane. "Everything takes time, he needs time, that’s it."
(Editing by Ken Ferris)
