Interest groups tore through President George W. Bush’s proposed health care reforms Thursday at Cambridge City Hall, saying many people would not be able to afford health care and prescription drug coverage would be cut under the plan.

Tiffany Skogstrom of Jobs with Justice said 39 cents of every dollar of Medicare taxes under Bush’s Medicare Reform Act would go to overhead such as administrative costs and not directly toward patient care. She said the added costs could be minimized with a program called Single Payer Care, which would reduce middlemen and cut costs.

The extra money is needed more now than later, she said, because 47 million Americans have no health insurance.

“Now it’s time to take health coverage off of the bargaining table once and for all,” Skogstrom said.

In June of 2000, the World Health Organization ranked the United States 37th among health care systems – a ranking Skogstrom said should be improved.

“The presidential campaign is a great opportunity for us to talk to candidates about our solution to the problems of health care,” she said. “You will see us at the Democratic National Convention this July.”

She said her organization is trying to influence all parties to improve health care, although it has had more success in the past with Democratic candidates. With 55,000 activists for health care reform, the issue should play a large role in the presidential debates, she said.

Cambridge resident Arvimla Sarazen said she suffers from heart and respiratory problems and that she is unhappy with her current coverage and Bush’s proposal to cut Medicare. She said she lost much of her health coverage at age 65.

“Medicine is a necessity, not a luxury,” Sarazen said, adding that Medicare does not cover the cost of her prescriptions.

“When you’re sick you don’t want to have to worry about the cost of your health,” Sarazen said.

Boston University Economics Department Chairman Laurence Kotlikoff, who has researched the costs and benefits of Medicare, said Bush’s prescription drug benefit plan would only reduce prices for a select few and would cost too much.

“We cannot afford it,” he said in a phone interview. “It will bring the nation into a state of bankruptcy.”

Former Cambridge mayor and health care activist Barbara Ackermann said insurance costs go up by double digits every year, and she estimated a 17 percent increase in insurance rates for this year. She said senior citizens currently pay half of health costs in addition to taxes for Medicare.

In addition to Jobs for Justice, members of the Massachusetts Nursing Association, the Massachusetts Senior Action Council and others attended the rally, which was organized for National Healthcare Action Day.

Paula Bromzoni, of the Massachusetts Association of Portuguese Speakers, said many legal immigrants who pay their taxes but are not citizens are denied health care coverage that she said should be guaranteed to them.

“We are afraid to go to the hospital … because we fear being turned over to the INS,” she said.

Many elderly individuals with signs reading “Health Care for All” and “$ for Health Care, not for Red Tape” stood behind the speakers.