Ferguson was responding to questions posed in relation to comments made by Manchester City striker Sergio Aguero earlier this week.
Asked if foreign players have it tougher than English players, he said: "Yes, always. It happens everywhere. There is a little bit of privilege with players who come from that country, but that is normal.
"We just play our game, and the referee's job is to know who is tricking him and who is not."
Pushed further on whether referees are a bit suspicious of foreign players, Aguero added: "Maybe, yes. It can happen, but I don't think it did here.
"If it does, it's not good for anyone. Here in England, there are almost as many foreign players as English players and it's not right that some have a privilege that others don't."
When questioned about this during the press conference prior to United's UEFA Champions League group match against Cluj, Ferguson said in comments quoted by the Guardian: "It's not worth going into that subject because down the years there have been plenty of players diving, and you have to say particularly foreign players."
Earlier, after his side's 3-2 loss to Tottenham on Saturday, Fergie had claimed Portuguese winger Nani should have had a penalty, and that he didn't might have been because he tried to make too much of it.
"I think the one in the first half was a clear penalty kick, but maybe Nani made a meal of it and he didn't need to do that. He was clearly pulled back," he said.
However, on Sunday, he jumped to his player's defence.
"Nani is not the type to dive, I know that. It was a penalty kick on Saturday. Sometimes you get them, sometimes you don't. The linesman could have helped him but didn't," said the Scot.