Members of Parliament are reviewing the rules that reject immigrants because they could be a drain on Canada's social services and health-care system.

As it stands, applicants can be refused if their condition is a potential danger to public health or safety, or if immigration officers believe they could cause "excessive demand" on the system.

Determinations are based on whether anticipated costs are expected to exceed the average Canadian per-capita health or social services costs over a five-year period, or if they could add to an existing waiting list that might delay care for Canadian citizens or permanent residents.

The immigration committee began its study this morning, hearing from officials in the immigration department on how the guidelines are currently applied and how they are being reviewed for possible adjustment.

Liberal MP and immigration committee chair Rob Oliphant said the government has signalled interest in the issue in the wake of high-profile cases, including the one of a York University professor whose application for permanent residency was turned down because his son has Down syndrome.

"If these are mostly economic migrants coming in and making money and paying taxes, is there really a net benefit, or is it a net cost? We don't know and we want to find out," he said.

Figures provided to CBC News from Immigration, Refugees and Citizenship Canada show a sharp decline in the number of applications rejected on medical grounds in the last three years. In 2016, 337 applicants were deemed inadmissible, down from 473 in 2015 and 619 in 2014.

Conservative immigration critic Michelle Rempel said the longstanding federal policy has attempted to strike a difficult balance.

"It's an issue that pulls at the heartstrings, because there are many cases of people who come to Canada with dire medical needs who will be found to be medically inadmissible," she said. "It brings out the compassionate care of Canadians."

Rempel wants to hear from witnesses on whether the policy is being applied adequately and consistently, and what the impact of any potential change could be on overall costs and waits for services for Canadians.

Newfoundland LIberal MP Nick Whalen said he felt "sheepish" even talking about putting a price tag on human lives.

"I mean, from a moral perspective, I don't know where the objective of the provision explicitly recognizes the sanctity of human life and equality of all people in our immigration system," he said.

"It just feels like doing a cost-benefit analysis on human beings and whether they should be in Canada makes me very morally squeamish."

Ability to pay not a factor

According to the rules around medical inadmissibility, a willingness or ability to pay is not a factor for services that are publicly funded like physician or hospital care, since there is no cost-recovery regime in place.

However, it is a consideration in assessing an applicant who has financial means to defray costs of medication or services that are not publicly funded, such as HIV antiretroviral therapy.

Ottawa-based immigration lawyer Ronalee Carey called the policy "two-faced" because it allows a discrimination against immigrants that would never be permitted against Canadians with intellectual or physical disabilities.

She said the estimated health costs of these potential immigrants is a small fraction of the total cost of the country's health-care system, and that the policy ignores other contributions the newcomers could make to society.

More than money

"It's more than just money and economics," she said. "It's a political decision and that's why we elect officials, but I would really ask them to look at what these people bring to us beyond a health-care problem. What does the entire family bring?"

NDP immigration critic Jenny Kwan said the system forces people with disabilities to go through a "separated and segregated" medical review.

"This, to me, is a textbook case of discrimination," she said.

Asking what disabilities could potentially deem a family inadmissible, an official confirmed that a family could be rejected if there is a child who is deaf or blind.

Identified public health and safety issues range from active pulmonary tuberculosis and untreated syphilis to mental health issues such as pedophilia, sociopathic behaviour disorders or paranoid states or substance abuse that can lead to violent, hostile or disruptive behaviour.

Immigration department official Dawn Edlund said the department is working on a review of guidelines with the goal of ensuring the current policies strike the right balance between protecting the integrity of publicly funded services and ensuring the immigration system is fair and compassionate.

MPs will also hear from legal and economic experts and advocacy groups for their ongoing study.