Volunteers are counting the number of homeless people in Vancouver on Monday and Tuesday. (CBC)

Volunteers are scouring the streets of Vancouver for homeless people, as part of a city-wide effort to determine just how many there are and if the number is growing.

Three-hundred volunteers checked soup kitchens, shelters, safe houses and transition houses on Monday night and plan to survey outdoor locations such as alleys, parks and under bridges on Tuesday night.

A larger regional count takes place every three years, with the next count scheduled for 2011, but Vancouver Mayor Gregor Robertson says he doesn't want to wait.

Vancouver has one of the highest populations of homeless in the region and the count will provide critical information needed to update Vancouver's homeless action plan, said Robertson, who has opened a number of emergency shelters since taking office in 2008.

Once the count is completed, the city should know whether the number of people without homes has changed over the past two years, and what medical and social services they are using, he said.

"It gives us a rough estimate of who is outside, who is in the shelters, and a very rough estimate of who is couch surfing or sleeping in cars," he said.

The volunteers are using the same methods as the regional count, but Robertson acknowledged counting the homeless is never an exact science.

"It gets very difficult for people that have a place that is maybe secure to them at a friend's, but they don't have a home, and that's a harder number to estimate. So it's not perfect, but it gives us a good idea," he said.

More than half-a-dozen emergency shelters are scheduled to close at the end of April.

The 2008 study found 2,600 homeless people across the Lower Mainland.

With files from The Canadian Press