With 65,000 employees and 1,100 flights per day, Toronto's Pearson International Airport is like a small city -- one that has some serious security shortfalls, says Sen. Pamela Wallin.

Wallin, deputy chair of the Senate Standing Committee on National Security and Defence, is helping conduct a border blitz at some of Canada's busiest entry points in an effort to identify problems and possible solutions.

The blitz began on Wednesday at Pearson, and Wallin and Sen. Colin Kenny, chair of the Senate Standing Committee on National Security and Defence, will also visit key border points in Windsor/Detroit and Niagara/Buffalo.

Roughly 86,000 passengers arrive and depart from Pearson on a daily basis.

"It is the 4th largest entry point into the United States of America so this needs to be one of our most secure border points. And we found some very troubling things," Wallin told CTV's Canada AM.

One of the problems they identified is the fact that very few of the airport's 65,000 employees go through security checks on their way to and from work.

While passengers, pilots and flight attendants all go through daily screenings, many employees who go through security clearance checks when they first get hired, don't have to undergo daily checks.

"They are not checked on a regular basis either coming in or going out of the airport, so that means potentially goods that should not be there, illegal goods or contraband, can be brought in and maybe placed on a plane, and illegal goods can be taken away from that airport without anybody knowing," Wallin said.

After speaking with border guards and officials, Wallin said most agreed that staff security checks are an area where the airport can improve its track record.

"They said look, we've got the equipment to do it, we should be able to do this, we need to do this because we know there is a lot of criminal activity," she said.

In addition to security concerns, Wallin and Kenny are looking at the flow of trade and how business can be improved.

She said the Ambassador Bridge between Windsor and Detroit is the largest trade nexus in the world.

"The Americans do more trade with Canada across that one bridge than they do with Europe, so we need to be looking at that."

Wallin and Kenny also hope to identify security shortfalls that allow high numbers of illegal immigrants to make their way into Canada.

She said there are roughly 25,000 people currently in Canada, who entered illegally. In the Greater Toronto Area alone, she said, there are between 35,000 and 40,000 outstanding warrants for people "who should not be in this country, but are."

"We don't what they're doing or where they are and that's troubling."