It has been suggested City will try to lure Bale to the Etihad Stadium with a big-money bid.
Friday's Daily Mirror reported that City were ready to make a £40 million offer for the Wales international, who last season was named PFA Player of the Year.
But Mancini does not think Spurs would be interested.
"Gareth Bale is a fantastic player," said the City boss. "But I don't think he will leave a big team like Tottenham."
Mancini also said that tentative discussions over the club's summer transfer policy have been put off until the end of the Premier League season.
"We talked about this some weeks ago," he said. "But now our focus has to be on the next two games."
City currently lead Manchester United on goal difference and visit Newcastle United on Sunday.
Mancini said fifth-placed Newcastle would approach the game in an extremely confident mood after their 2-0 victory at Champions League finalists Chelsea on Wednesday.
"Newcastle played a fantastic game at Chelsea and I think this game will be more difficult for us," Mancini told reporters on Friday.
"The Manchester United game was at home and we played very well to win 1-0 but Newcastle is away and I think it will be harder."
The two Manchester clubs are locked together on 83 points with two games left to play this season.
Mancini said City would keep a particularly close eye on red-hot Senegal striker Papiss Cisse on Sunday.
"Cisse is incredible," said the Italian. "He scored two fantastic goals against Chelsea.
"He has 13 goals in 12 league games for Newcastle and he's a good player. But not just him, their whole team is playing very well.
"They play to win in every game, they have a good mentality and for this reason I think it will be a good game on Sunday."
Manchester United entertain Swansea City and Mancini dismissed the suggestion that Manchester City would be under more pressure because they play first on Sunday.
"Our players know they have everything in their own hands," he said.