OTTAWA -- Hundreds of frustrated scientists clad in their telltale white lab coats descended Monday on Parliament Hill to demand that the Harper government stop muzzling scientists and cutting research funding.

"What do we want? Evidence-based decision-making!" chanted the protesters as they gathered in the shadow of the Peace Tower, complaining about what they see as the government's efforts to commercialize research.

The very fact that such a typically apolitical group felt the need to make their voices heard speaks volumes, said Jeremy Kerr, a biology professor at the University of Ottawa.

"As a commentary on the state of affairs, when people like me start showing up wearing their lab coats having come from their laboratories, things are pretty bleak," Kerr told the crowd.

The fundamental message is "simplicity itself," Kerr said: "Sound policy needs sound science."

"The facts do not change just because the Harper government has chosen ignorance over evidence and ideology over honesty."

The Ottawa rally was part of a national series of "Stand Up for Science" protests taking place across the country, organized by Ottawa-based science advocacy group Evidence for Democracy.

The group argues that evidence-based decision-making must inform governmental funding decisions on science. They say current funding has instead shifted towards commercialization of research.

"They want us to put aside what we're doing and shift our efforts towards industry and to force us to do that they shift their money towards earmarked projects," said Bela Joos, a University of Ottawa physics professor.

One protester attached a telescope to a bike helmet and carried a sign that read, "Desperately seeking intelligent life on Parliament Hill!"

Greg Rickford, minister of state for science and technology, defended the government in an emailed statement that did not directly acknowledge the protest nor the specific concerns raised by the scientists.

"Our government is committed to science, technology and innovation and taking ideas to the marketplace," Rickford said. "Canada is ranked number one in the G7 for our higher education research and development."

Scientists also argue that government cuts have reduced public science projects aimed at helping average Canadians in sectors like health and the environment.

They're also upset about reports that the Conservative government has taken steps to restrict what scientists and other civil servants are allowed to say to the media.

The Environmental Law Centre at the University of Victoria and the ethics advocacy group Democracy Watch has cited multiple examples of taxpayer-funded science being suppressed or limited to pre-packaged media lines across six different government departments and agencies.

"Cuts to essential scientific programs and services have undermined our society's scientists' ability to serve the public good," said Gary Corbett, president of the Professional Institute of the Public Service of Canada.

New Democrat Leader Tom Mulcair said the concept of fact-based decision-making goes "completely against the grain" for Prime Minister Stephen Harper and his government.

"The use of scientific information is something that bolsters our ability to protect the public," Mulcair said.

"Stephen Harper's shutting down of scientists -- of firing them, or of muzzling the ones he hasn't fired -- is for us an approach that goes completely against the nature of a Parliament where things have to be debated openly."