More than 800 scientists from outside of Canada have signed an open letter to Prime Minister Stephen Harper calling for an end to funding cuts to the country's science programs.

The letter, which was released Tuesday by the U.S.-based Union of Concerned Scientists and the Professional Institute of the Public Service of Canada (PIPSC), also calls on the government to remove barriers so that government scientists are able to freely collaborate internationally to help fight major environmental and health threats.

"Meeting today's complex environmental and public health challenges requires the full participation of scientists around the globe," the letter reads. "But recent reports highlight a rapid decline in freedoms and funding extended to Canadian government scientists, which make it more difficult for them to continue research, communicate scientific information and expertise, and collaborate internationally."

The letter makes reference to a New York Times editorial published in 2013, which described the alleged communications restrictions put on Canadian government scientists as an "attempt to guarantee public ignorance" on the environmental impact of Alberta's oil sands.

The scientists who signed the letter come from research institutes and universities from 32 different countries. They include researchers from Harvard Medical School, Google and the Max Planck Institute in Germany.

The letter was brought up Tuesday afternoon in the House of Commons during daily question period.

“The government can no longer deny that by cutting science budgets and muzzling Canadian scientists, they are damaging Canada’s international reputation,” said New Democrat MP Lauren Liu. “Will the government finally wake up and stop treating scientists like enemies?”

Ed Holder, minister of state for science and technology, responded by saying the Conservative government has made “record investments” in science, technology and innovation. He said that Canada is ranked first in the G7 for research and development at our colleges, universities and other institutions.

“Our government has invested $1.5 billion of new money for the creation of the Canada First Research Excellence Fund, which allows institutions to leverage world-class strengths into world-leading research that will create long-term benefits for Canada,” Holder said.

Two PIPSC reports released in 2013 shed light on how federal government scientists feel about funding cuts and the new restrictions they face at work.

The reports shared the results from a survey of over 4,000 government scientists. The survey found that 90 per cent of federal scientists don't feel that they can speak freely to the media about their research, and 91 per cent believe funding cuts are negatively impacting the government's ability to serve the public interest. 

The survey also found that 36 per cent of federal scientists are approved to attend international conferences on their field of research.

The release of Tuesday's letter coincides with the federal government's Science and Technology week, and is being accompanied by an advertising campaign that stresses the importance of increased international scientific collaboration.