Canada Post and its postal workers appear far apart on substantive labour and compensation issues only three days before a strike could be in full effect.

The union representing the postal workers has submitted its final offer to the Crown corporation and is in a legal position to strike as of Thursday night.

If a strike goes ahead, some 48,000 postal workers could be out on picket lines as of Friday morning.

The two sides remain at odds over wages and the way that sick leave will be dealt with in the next contract, as well as the way the postal service is being modernized.

But Jon Hamilton, the director of communications at Canada Post, said Tuesday that postal workers and their union must realize that the future postal service will not be the same as it is today.

"We do have to face facts and we've seen a 17 per cent drop in mail volumes over the past five years," Hamilton told CTV's Canada AM on Tuesday morning.

Hamilton said Canada Post has spent $2 billion in recent years to improve and modernize its equipment, which has created some anxiety among postal workers.

He said Canada Post has made investments with careful consideration about the impact on staff.

"There have been tons of advancements in technology that we're bringing on to the work floor. We're looking at new work methods and they are safer than anything that we've done in the past," said Hamilton.

"It's a change and people have to adjust to that."

However, the Canadian Union of Postal Workers does not favour all of these changes, with union leadership voicing concerns about the way they are being implemented.

Union president Denis Lemelin told CTV's Canada AM that the new technology poses potential problems for postal workers at mail sorting facilities, as well as for staff tasked with delivering the mail to homes and businesses.

"This new technology will change the way we process and deliver mail. And for us, it's really important that this new technology be safe for our workers," Lemelin told CTV's Canada AM, moments before Hamilton appeared on the same Tuesday morning broadcast.

Lemelin said indoor workers may find themselves at increased risk of repetitive strain injury when using newer equipment that operates much more quickly than in the past.

Outdoor workers, on the other hand, are being asked to cart several separate mail types along their routes at the same time, which Lemelin said is problematic for carriers.

Hamilton said that Canada Post would "never bring forward or spend $2 billion to make our workplace less safe than it is today. That just wouldn't make any sense from a business standpoint."

Letter carrier Donalda Lavoie objects to the perception that delivering the mail by hand is becoming obsolete in the 21st century. She agreed that volumes of first-class mail have gone down. However, she said many of the homes and businesses on her combined business and residential Vancouver Island route still receive important documents -- from cheques to passports to correspondence from lawyers -- via Canada Post.

"You have a day-to-day relationship with all the people on your route, and it's more than just delivering mail," Lavoie told CTV.ca Tuesday in a telephone interview. "And that is really not taken into consideration anymore in this day and age."

"A strike leaves no one as a winner," she later added.

When the union sent in its final offer to Canada Post on Monday, it said it was "confident" that the Crown corporation could accept its terms as a basis of settlement.

In response, Canada Post said the union offer was "out of touch" with the challenges the postal service is facing.

Lavoie said one area of key concern for workers is the company's desire to scrap the short-term disability program. She argues that would create a "tax on every Canadian" because workers would be forced to apply for Employment Insurance if they suffered injuries not covered by WorkSafeBC, the province's workplace compensation board, or sick pay.

Canada has not seen a postal strike since the fall of 1997, when postal workers were off the job for two weeks. They were later forced back to work by federal legislation.

While mail and parcels will not be delivered if a strike takes place, volunteer workers have agreed to deliver cheques to pensioners and those on social assistance.

With files from The Canadian Press