As a science journalist working on a piece about climate change, Stephen Strauss was doing what he always does when he's trying to track down a story -- doing background research, coming up with questions, then lining up interviews with the best experts on the topic.

But he ran smack into a brick wall when the government refused to allow him access to federal scientists who could discuss the issue.

"I tried to reach them, I sent emails, I made phone calls, nothing. I thought this was odd because what I'm trying to explain to people is really the difficulty of dealing with this, there's no scandal here," Strauss told CTV's Canada AM.

"I found out all kinds of journalists were running into the same problem."

Strauss, vice-president of the Canadian Science Writers' Association, was trying to write about the challenges of climate change and the effects of methane gas emitted from cows.

It turns out the definitive paper on the subject was written by scientists from Agriculture Canada -- but no one would speak to him. They were muzzled, he claims, by the Conservative government.

It's a dilemma many Canadian science writers have complained about, and even the highly-regarded journal Nature recently published an editorial on the subject.

The editorial said Canada and the U.S. have recently undergone a role reversal. While the U.S. has adopted more open policies on releasing its research and freeing up its scientists to discuss their work, Canada has gone the other way.

And two weeks ago, the Canadian Science Writers' Association, the World Federation of Science Journalists and several other groups sent an open letter to Prime Minister Stephen Harper, calling on him to loosen the restrictions on government scientists and researchers.

The letter cited an example last fall when Environment Canada refused to allow Dr. David Tarasick to speak to journalists about his ozone layer research when it was published in Nature.

Strauss said there appears to have been a top-down directive that has drastically changed the relationship between government scientists and journalists -- particularly when the results of the research don't fit the government's agenda.

"I had a conversation with a government information officer, one who was nearly in tears describing how her job had changed from one in which her job was to facilitate communication between journalists and scientists to one in which her job was really to prevent the journalists from talking to the scientists.

"She felt like she couldn't do her job anymore," he said.

The Prime Minister's Office denies that claim. In a statement sent to CTV's Canada AM, the PMO defended its record.

"The government of Canada is proud of the research done by its scientists. Last year Environment Canada officials completed over 1,200 media interviews including more than 325 interviews with departmental scientists," the statement said.

Strauss said often when scientists are permitted to do interviews, the journalist must first submit all questions in writing -- a process that prevents follow-up questions and often restricts the flow of the conversation.

He said the U.S. has resolved the issue by allowing scientists to speak in both an official capacity, as government employees, but then also allowing them the freedom to set aside their official role when it comes to controversial issues, and go off-script and speak simply as experts in their field.

That approach has worked in the U.S. and could be successfully adopted here, Strauss said.

"From a perspective of the general public you actually want journalists to know what's going on, you want them to speak to the best people. As Canadians we want to learn what our Canadian scientists are doing in the best fashion, in the clearest fashion," Strauss said.

"This not only hurts journalists, this hurts the Canadian public and people who want to understand what really happened."