The secretaries of the departments of Veterans Affairs and Housing and Urban Development will argue the case for more funding to meet the Obama administration’s goal of ending veterans’ homelessness by 2015 at a conference Wednesday morning in Washington.

Secretary Eric K. Shinseki and HUD Secretary Shaun Donovan are scheduled to give keynote address during the opening session of the 2012 Annual Conference of the National Coalition for Homeless Veterans (NCHV) in downtown Washington.

The results in reducing the number of homeless veterans “allow us to make the case for more investments in a tough budget environment,” Donovan said in remarks prepared for the conference.

The number of homeless veterans found in point-in-time counts dropped 12 percent from 2010 to 2011, a decline Donovan attributed to the government’s embrace of the “housing first” strategy to combat homelessness.

“For decades, the federal government used to say to somebody living in the streets with substance abuse, for example, ‘Get sober — and then we’ll help you find a place to live,” Donovan said in his prepared remarks. “... That approach had it absolutely backwards.”

More than 30,000 veterans have been housed thus far through the HUD-VASH program, which combines housing vouchers issued by HUD with VA case management and clinical services.

HUD’s 2013 budget includes an additional $75 million for HUD-VASH, an increase of about 15 percent.

“That’s funding we need to fight for,” Donovan said, according to the prepared remarks.

A new, comprehensive Homeless Veterans Registry several years in the making will be rolled out this summer that will help researchers study the causes of homelessness and the forces that keep homeless on the streets, according to Shinseki.

“With this registry, we’ll be able to clearly validate our needs, see where to apply our resources, and then measure whether we did any good,” Shinseki said in remarks prepared for the conference.

Shinseki said that ending veterans homelessness will require “both rescue and prevention — rescue those on the streets today, and at the same time, prevent others who are at risk of homelessness from ending up there tomorrow or the day after.”

NCHV chairman Pat Ryan said there has been “unprecedented national unity” to end veterans’ homelessness. “The progress we have seen from the federal agencies, the Congress, the community partners NCHV represents, and the American people in just the last three years give rise to the expectation that this campaign will succeed,” he said.

More than 500 representatives of government agencies and community-based organizations will be attending the three-day training conference, which is titled “Halfway Home: Progress in the Five-Year Plan to End Veteran Homelessness.”

Among the topics will be numbers showing an increase in homelessness among female veterans.

The Home Depot Foundation, which last year launched a three-year, $30 million initiative to increase housing for homeless and extremely low-income veterans, is sponsoring the conference.