Porter Airlines has been fined for violating the CRTC's anti-spam legislation.

The CRTC says the Toronto-based airline has agreed to pay a $150,000 fine for sending e-mails without an unsubscribe button or one that was clearly labelled.

The federal regulator alleges the violations took place between July 2014 and April 2015.

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Porter could not immediately be reached for comment.

The CRTC says Porter was also unable to provide proof of consent from each email address that received its commercial e-mails.

The regulator says as part of the agreement with the company, Porter has agreed to improve its compliance training for the anti-spam legislation.

Since last July, the regulator has also fined online dating website PlentyOfFish and corporate training company Compu-Finder for unwanted e-mail messages.

"Some businesses are under the mistaken impression that they are compliant with the law by relying on general business practices or policies as proof of consent," said chief compliance and enforcement officer Manon Bombardier. "This is simply not the case."