Some Calgary companies and non-profit groups say complying with the country's new anti-spam legislation is proving to be difficult.

The rules that take effect on Tuesday some of the most stringent in the world are meant to protect Canadians from unwanted emails and social media messages.

"So what we have to worry about is that anything we email, electronic communication, we have consent," said Areni Kelleppan, executive director of Green Calgary.

But it has been a nightmare trying to get permission from customers and subscribers to continue to send them emails and newsletters after July 1, she said. Out of 5,000 contacts, just 1,600 have replied so far.

The organization’s mailing list is used to attract corporate sponsors.

"If they don't see the value, or don't see the numbers, they might not be giving in the same way they used to. That could significantly impact the accessibility for all Calgarians, so that's a significant issue for us.”

Guillaume Bedard, who owns Alberta Weinstein, an online company that ships boutique wine and specialty cheese and meat, said introducing the new rules in the summer has made things difficult.

"Because it’s the beginning of the vacation period and people are not actually inclined to look into their inbox to respond as promptly as we wish."

But lawyer Jeff Kahane says the law is clear and companies need to respect the wishes of their client base.

And failing to comply will be expensive, he said.

"The penalties are for an individual up to $1 million per transaction, for companies, it’s up to $10 million. So those are pretty steep.”

There are some exemptions but it’s best to proceed as though consent is required, Kahane said.