However, he said: “I’m probably about the only politician I know of who is actually willing to stand up and say that he’s pro-immigration.”
“I believe that when talented people have something to offer a society and a community they should be given the benefit of the doubt,” Mr Johnson added.
Some backbenchers have voiced the opinion that Mr Johnson is the only Conservative capable of combating the threat to the Tories from the UK Independence Party.
However, the Mayor’s views on migration could distance him from backbenchers if he was to ever attempt to become the Conservative leader.
Earlier this year, Mr Johnson called for a one-off amnesty for illegal immigrants.
He challenged the Coalition’s opposition to an amnesty and said that illegal immigrants should be allowed to stay after 12 years in Britain.
Mr Johnson said on Wednesday: “I’m not going to resile from or going to dismiss the notion that you’ve got to be tough on illegal immigration.
“Frankly it was, if I may so, the active decision of the Labour government to turn a complete blind eye that undermined immigration in the eyes of many people in this country.
“And you should think about that because it did serious social damage.”
He added: “I go back in a pedantic way to this distinction between legal and illegal immigration. It is vital that we do make that distinction. I’m probably about the only politician I know of who is actually willing to stand up and say that he’s pro-immigration.”
Mr Johnson then jokes that the only other people backing immigration are the Green Party.
“I’ve got the support of the Greens, great,” Mr Johnson added. “We can build on that. Labour being very quiet, I notice. I believe that when talented people have something to offer a society and a community they should be given the benefit of the doubt and I speak as the descendant of immigrants and all the rest of it.
“But you’ve got to be very, very tough in dealing with people who break the law. They are undermining the credentials and the hard work of everybody else.”