The National Park Service is giving people more time to weigh in on a proposed fee increase at 17 of its most popular parks-- including Denali. 

Visitors would be charged $70 per vehicle, up from the current $25 to $30 fee, during the five busiest months of the year. Under the agency's proposal, the cost for a motorcycle entering the park could increase to $50, from the current fee of $15 to $25. The cost for people entering the park on foot or by bike could go to $30, up from the current rate of $10 to $15.

The cost of the annual pass, which permits entrance into all federal lands and parks, would remain at $80.

The comment period had been scheduled to end Thursday. The new deadline is Dec. 22. The Park Service said it wanted to accommodate interest from Congress and the public. More than 65,000 comments already have been submitted.

The Park Service says it would raise $70 million annually under the proposal. The revenue would fund maintenance and infrastructure projects, including to roads, bridges, campgrounds, waterlines, bathrooms and other visitor services at the parks.

The proposal would affect the following 17 national parks during the 2018 peak season:
Bryce Canyon
Grand Canyon
Grand Teton
Sequoia & Kings Canyon
Mount Rainier
Rocky Mountain
Joshua Tree
"The infrastructure of our national parks is aging and in need of renovation and restoration," Secretary of the Interior Ryan Zinke said in a statement when the proposal was first announced.

Of the 417 national park sites, 118 charge an entrance fee.

The proposal was blasted by the National Parks Conservation Association, a nonpartisan advocacy group.

"We should not increase fees to such a degree as to make these places -- protected for all Americans to experience -- unaffordable for some families to visit," the group's president and CEO Theresa Pierno said in a statement. "The solution to our parks' repair needs cannot and should not be largely shouldered by its visitors."

"The administration just proposed a major cut to the National Park Service budget even as parks struggle with billions of dollars in needed repairs," Pierno said. "If the administration wants to support national parks, it needs to walk the walk and work with Congress to address the maintenance backlog."

On the National Park Service's Facebook page, some commented that the proposal was reasonable since it was going to improve and maintain the parks. Others lamented that it would price working class people out of making trips that they had saved up for.

Entrance fees at several national parks, including Mount Rainer, Grand Teton and Yellowstone, went up in 2015 to their current price.

Those fee increases didn't seem to deter visitors. In 2016, National Park Services received a record-breaking 331 million visits, which marked a 7.7 percent increase over 2015. It was the park service's third consecutive all-time attendance record.

Most popular National Parks in 2016 (59 total)

Great Smoky Mountains National Park -- 11,312,786 million visitors
Grand Canyon National Park -- 5,969,811
Yosemite National Park -- 5,028,868
Rocky Mountain National Park -- 4,517,585
Zion National Park -- 4,295,127
Yellowstone National Park -- 4,257,177
Olympic National Park -- 3,390,221
Acadia National Park -- 3,303,393
Grand Teton National Park -- 3,270,076
Glacier National Park -- 2,946,681

CNN's Katia Hetter and the Associated Press contributed to this report.