The union for postal workers in Nova Scotia says Canada Post's new delivery system has resulted in longer hours, more injuries and stress for their letter carriers.

Trevor Beckerson, the president of the Canadian Union of Postal Workers Nova Local, said injuries to letter carriers have increased by as much as 30 per cent in Halifax since the delivery system was changed in August.

"The problem with this new delivery model is it forces letter carriers to be out longer, which increases their risk of injury," Beckerson told CBC News.

"They're out into the dark all the time, which further increases the risk of injuries."

Canada Post is phasing out its system of using three separate trucks to drop mail off at collection boxes, deliver parcels and pick up outgoing mail.

In August, letter carriers in Halifax began using one van to perform these tasks, in the first test of the new system on the East Coast.

It's all part of the corporation's $2-billion modernization plan, which includes investments in equipment, systems and buildings all over Canada.

Reggie Jones, who has been delivering mail for 24 years, said he's never had to work such long hours.

"You kind of feel like you're doing something wrong or something because you're working so late," Jones said.

"I'm working overtime most days and a lot of days are 10- and 11-hour days."

Canada Post said the modernization plan was put in place because the corporation had seen a 15 per cent decline in letter mail over the past five or six years.

Porchlights for Posties campaign

A spokeswoman for the company admitted there have been problems with the new delivery system.

"It's taking us some time to stabilize those changes," said Denise Corra.

"Our employees have worked a lot of overtime; we know that. We really appreciate the work they've done. We have some issues."

The Canadian Union of Postal Workers is pushing back against the changes with a national campaign called Porchlights for Posties, which encourages homeowners to keep their outdoor lights on until the mail is delivered after dark.

The union also wants to highlight what they say the letter carriers are dealing with on the job.

"Letter carriers are very strained, they're very upset. We've had a lot of people dealing with a lot of stress issues around this," said Beckerson.

"Letter carriers are finding it very, very hard to have any sort of personal life or any sort of work balance. It's very difficult to have a good life when you start your day at 8 o'clock in the morning and you end your day at 8 o'clock at night."

Canada Post is expected to deliver one billion cards, packages and letters in December over the holiday season.

The union's campaign is encouraging people to express concerns to their local MP.