Union leaders are warning Canadians to expect shorter operating seasons and fewer services at national parks and historic sites, after more than 1,000 Parks Canada employees received notice Monday that their jobs may be at risk.

More than 3,800 civil servants across various government departments received the dreaded notices in the latest round of budget cuts.

The Conservative government aims to eliminate about 19,000 federal jobs in an effort to save $5.2 billion over the next three years.

However, the government has said that many affected employees will be able to apply for other government positions or accept retirement packages.

Parks Canada took a big hit on Monday when employees were told that more than 600 positions will be eliminated entirely.

As a result, Canadians won't be able to enjoy the country's natural wonders like they used to, said Larry Rousseau of the Public Service Alliance of Canada.

"When you drive up (to a park) and you expect people to explain to you the services that are available, the best trails to go to…you might not get that," he told CTV's Power Play on Monday. "That personal touch is definitely going out the window."

Other departments affected by job cuts include Human Resources, Aboriginal Affairs, Library and Archives and Statistics Canada.

Cuts will also be made to airport and marine security branches at Transport Canada, said Christine Collins, national president of the Union of Canadian Transportation Employees.

"While all of these cuts are happening in the name of savings, senior executives throughout government will receive hefty bonuses for doing these cuts. Shame on them," she said.

"It's a budget about jobs and growth yet we're cutting jobs and even the economists are saying that with these kinds of cuts, you're really cutting into growth as well," Rousseau said.

"This government is saying one thing and they're doing another."

So far, nearly 12,000 people in 40 government departments and agencies have been told their jobs are in danger, said John Gordon, the president of the Public Service Alliance of Canada.

The government previously announced cutbacks at the Canadian Food Inspection Agency, angering critics who say Canadians' lives may be on the line as a result.

At Correctional Services Canada, the inmate grievance program has been closed. The Conservatives recently announced the closure of two federal prisons, including the historic Kingston Penitentiary.

To protest the cuts, union leaders are planning a major rally on Parliament Hill on Tuesday.

"Tomorrow is May Day. You're going to see, for the first time, there's going to be a lot of people out on the streets on May Day," Rousseau said.

With files from The Canadian Press