The Harper government is urging Canadians to help fund relief efforts in Pakistan, a day after announcing it will match private donations to the flood-ravaged country.

"Looking at the need that's getting stronger, we're making an appeal to Canadians to join us," Government House Leader John Baird told CTV's Canada AM on Monday.

Baird announced Sunday the government will go dollar-for-dollar on qualifying donations made by Canadians between Aug. 2 and Sept. 12.

No limit has been set on the government's contribution, which will go to continuing humanitarian assistance, as well as recovery and reconstruction efforts, he said.

The government initiative is giving hope to relief organizations, who say aid funding in response to the devastating floods has been sluggish so far.

"It's great timing, because one of the concerns we've had is the very slow response for public donations to this crisis, so maybe this will help stimulate some of that," CARE Canada's Waleed Rauf said from Islamabad, Pakistan.

The floods, which began in July after monsoon rains, have affected 20 million people and left roughly six million homeless.

The United Nations World Food Programme on Sunday sent the first three of five helicopters meant to deliver food and assistance in Pakistan. The organization estimates another 40 helicopters are required to reach communities now inaccessible by land.

Canada's donation-matching initiative is a similar strategy to what the Harper government did in the wake of the devastation following the January earthquake in Haiti. Back then, Ottawa matched tens of millions of dollars that Canadians gave in private donations for the recovery in Haiti.

But Baird said the two disasters unfolded very differently.

"In the case of Haiti, for example, you had upwards of 200,000, a quarter of a million people, killed in less than a minute some three hours from Canada," he said Sunday. "Obviously the flooding has been incredibly different. It's gotten progressively worse."

Dave Toycen of World Vision Canada said prior dollar-for-dollar measures have been effective in raising donations.

Prior to Sunday's announcement, Canada had pledged $33 million for flood relief in Pakistan, which Liberal MP Jim Karygiannis had called "a drop in the bucket" in terms of what is needed.

But Baird defended the government's efforts to help out the people in Pakistan.

"To those who say we're not doing enough, we're the fifth largest contributor in the world," he said.

In Pakistan, Foreign Minister Shah Mahmood Qureshi said Sunday that pledges and donations had topped US$800 million.

With files from The Associated Press and The Canadian Press