At the same time, the report by Canadian Journalists for Free Expression takes aim at the Conservative government for its "culture of secrecy" as epitomized by the muzzling of federal scientists.
"There are good reasons to go even lower than last year's failing F," states the "Review of Free Expression Canada" released ahead of Friday's World Press Freedom Day.
"But rather than repeating this dismal year, we hope the federal government will heed the many voices calling for change."
The group's 2012-2013 report gives the federal government a C-minus overall, and a D-minus for its access to information law.
Among other things, Canada's "archaic" law governing access to information ranked 55th out of 93 countries that have such laws, the report says.
It also notes statistics on delays and withholding of information show an increasing opacity when it comes to government.
"We have been concerned for some time about the growing stranglehold on information available to Canadians," CJFE president Arnold Amber said in a statement.
"It is systemic. Its roots burrow across government departments and across Canada. It is a sickness debilitating our democracy."
Among signs of hope, the report points to government plans to make summaries of completed access to information requests searchable across all departments and a push by Information Commissioner Suzanne Legault to update the act.
The report is especially scathing of the Dept. of Fisheries and Oceans — it gets an F — for "its zeal in muzzling scientists, controlling its message and keeping critical information away from the public."
Among other things, the department refused to allow media access to one of its researchers, Kristi Miller, who wrote a peer-reviewed study on salmon diseases.
Legault has launched an investigation into the government's control of its scientists.
In a statement Thursday, Matthew Conway, spokesman for Treasury Board President Tony Clement, called the government "the most open and transparent government in Canadian history."
Conway said the government has expanded access laws to cover more agencies, and completed access requests have doubled over the past decade.
He also said communications guidelines for scientists have not changed in more than a decade.
"Government scientists and experts are readily available to share their research with the media and the public," Conway said.
The CJFE report gives the Parliamentary Budget Office — formerly led by Kevin Page — top marks for its contribution to the discourse about transparency and accountability of government.
"Page made it his duty to tackle difficult and controversial issues with integrity and conviction, and to communicate to Canadians much-needed information about these issues," the report states.
Page, whose term was not renewed, often found himself at odds with the government, which accused him of overstepping his bounds. Among other things, he criticized the cost of the Afghanistan mission and the proposed F-35 fighter-jet purchase.
He even took the government to court over his difficulty in obtaining information about its austerity measures.
"Part of the problem is simply the lack of political will to respect the fundamental rights of citizens to hold their government to account," the report states.
"Another part of the problem is that the Access to Information Act is now 30 years old, and its age is showing — it is desperately in need of reforms."