Kane, the club's top scorer with 31 goals last season, has not managed one in the new campaign.
Alli, 19, has burst into the first team recently and is already being tipped to follow Kane into the England squad.
"We must stop speaking about Harry Kane," Pochettino said at a news conference ahead of Saturday's game at home to league leaders Manchester City.
"We must let him do his job. The most important thing is I am very happy with his effort and the way he plays.
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"I think he can improve his quality. This is a tough moment but the people around the club and in the changing room -- we believe in him."
Alli, who joined the club from Milton Keynes Dons, is under the same spotlight as Kane was last season, the manager added.
"Be careful with the younger players, the players who arrive in the Premier League and perform well. It's not easy.
"You can see he's a player that is very mature and shows great quality but always in football it's step by step and we need to be careful.
"He will mature. He has personality and good character. But it is too much of a rush to talk about bigger steps for him.
"Like last season, it's not my decision. It's (England manager) Roy Hodgson's decision if he wants to call up Dele Alli."
Spurs have lost their last four meetings with City, conceding 16 goals, but Pochettino said his team are over the disappointment of losing a North London derby at home to Arsenal in the League Cup on Wednesday.
"It is always a little bit sad when you lose a derby, but the thing is in football it's impossible to stop," he told Tottenham Hotspur TV.
"You have to be ready for the next game. It's a good opportunity to change the dynamic."
Midfielders Ryan Mason and Mousa Dembele are still out injured.
(Reporting by Steve Tongue; editing by Toby Davis)
