Former US president Jimmy Carter helps build a house as he visits the construction site of houses being built by Carter's Habitat for Humanity foundation for victims of the earthquake in Leogane, Haiti in 2012.

Former President Jimmy Carter told CNBC this week that the Trump administration is ignoring a national housing crisis, and he urged voters to support candidates who promote affordable housing.

"Low-income housing needs to be raised much higher as a priority for our country," Carter said in a phone interview. "That's the first step toward making people who are now dependent on government assistance, on welfare rolls, to get a good job and have a chance to raise their families and put their kids through school."

Carter, a Nobel Peace Prize winner who turns 94 in October, also called for broad reform for the U.S. Department of Housing and Urban Development. He said this fall's elections offer voters a chance to support an issue that has been widely overlooked by candidates in this year's midterm election cycle.

In response to a request for comment, a HUD spokesman referred CNBC to the department's website but did not answer specific questions.

Since the 2008 financial crisis, the housing market has broadly recovered overall. But many Americans have been left behind. Millions of low-income Americans are paying 70 percent or more of their incomes on housing and face a shortage of available affordable rental apartments.

Carter said the gap between rich and poor has reached unprecedented levels as land becomes scarce and the cost of homebuilding rises.

Meanwhile, HUD Secretary Ben Carson has proposed tripling the minimum rent paid by the poorest public-housing tenants and rolling back rent restrictions on 4.5 million households that participate in public housing programs, according to HUD data.

The White House's fiscal year 2019 budget proposal also slashes funding for HUD by $8.8 billion and calls for work requirements for those who receive public housing subsidies. The administration has also proposed raising the minimum rent for the poorest families to about $150 a month — three times the current minimum.

Carson has said the goal is to reduce assistance to the poor to combat what he sees as a cycle of dependency. Proponents of this approach argue that while safety-net programs are important, low-income renters and homeowners who rely on too much federal assistance will become stuck in dependent situations.

But Carter, who has helped renovate 4,300 homes in 14 countries for Habitat for Humanity, said the policy is misguided. Rather than becoming more dependent on government, he said, the people who move into Habitat homes and receive public assistance are "hardworking" and become productive citizens and taxpayers.

"I don't think that making people self-sufficient who are already in desperate need and who have never had a decent place to live is a good approach to low-income housing," he said. "You can make people suffer longer by depriving them of adequate help."

Facing increased demand and rising land prices, Habitat housing has become more expensive. The cost of building a home 35 years ago was roughly $20,000 to $25,000 and has since more than quadrupled, Carter said.

"The main thing that we have failed to do is to let people in general join in with Habitat and emphasize the need for low-income housing," he said.