Japan international Minamino moved to Anfield from RB Salzburg in January, but has struggled for playing time among the Reds firing front-three.
Okazaki told the Evening Standard of Minamino: "I watch some of the games on TV and I don't see negative things.
"He plays well with and without the ball. He is getting confidence after he changed team.
"I know the Premier League is the hardest league in the world. Every season they spend a lot of money and Liverpool was the last winner of the Champions League and already had quality in their squad.
"But he can improve himself and I think that's important for him and Japanese football.
"At first, he just had quality but now he knows how to fight, he is quicker - he changed his style of play in the last two years."
"Now, we see that it is time for Japanese football to go to the next step. We need players in Europe playing every week in the biggest teams."