Nicholson made the comment in a statement after six countries announced they had reached an agreement with Iran on Thursday to limit Iran's nuclear program, to block it from developing atomic weapons.
A final accord is expected this summer.
Nicholson says if Iran had nuclear weapons it would provoke a nuclear arms race in the Middle East, and therefore "every diplomatic measure must be taken to ensure Iran never obtains a nuclear weapons capability."
The minister adds that Iran does not have a track record of being trustworthy. Therefore, he says, Canada is contributing $3 million to support the International Atomic Energy Agency's efforts to monitor Iranian compliance.
NDP critic Paul Dewar also stressed the importance of verification.Suggest a correction