WASHINGTON — More than one-third of calls to a suicide hotline for troubled veterans are not being answered by front-line staffers because of poor work habits and other problems at the Department of Veterans Affairs, according to the hotline’s former director.

Some hotline workers handle fewer than five calls per day and leave before their shifts end, even as crisis calls have increased sharply in recent years, said Greg Hughes, the former director of the VA’s Veterans Crisis Line. Hughes said in an internal email that some crisis line staffers “spend very little time on the phone or engaged in assigned productive activity.” Coverage at the crisis line suffers “because we have staff who routinely request to leave early,” he said.

An average of 35 to 40 percent of crisis calls received in May rolled over to back-up centers where workers have less training to deal with veterans’ problems, said Hughes, who left his post in June, weeks after sending the emails.

The House on Monday unanimously approved a bill requiring the VA to ensure that all telephone calls, text messages and other communications received by the crisis line are answered in a timely manner by an appropriately qualified person. The bill now goes to the Senate.

Rep. David Young, R-Iowa, the bill’s sponsor, said a veteran in his district told him he repeatedly received a busy signal when he called the crisis line this spring. The man later got help from a friend, but “this hotline let him down,” Young said. “A veteran in need cannot wait for help, and any incident where a veteran has trouble with the Veterans Crisis Line is simply unacceptable.”

The VA said Monday it is increasing staff at the New York-based hotline and opening a new hub in Atlanta. The agency also pledged to continue efforts to improve training, as it responds to a report by an internal watchdog that said crisis calls are routinely allowed to go into voicemail and callers do not always receive immediate assistance.

David Shulkin, the VA’s undersecretary for health, called veterans’ suicide a public health crisis and said suicide prevention is a top priority at VA. An estimated 20 veterans commit suicide every day; the vast majority were not connected to VA care in the last year of their lives, Shulkin said.

The toll-free hotline number is 800-273-8255.