The shortages "explain why there are waiting lists at all the hospitals".
Hospitals in crisis-hit Venezuela are facing shortages of about eight in 10 medications and medical supplies needed to treat patients, according to a study published Tuesday.
The 2016 National Hospital Survey found that 76 percent of the medicines and 81 percent of the medical and surgical supplies that doctors need had run out or were hit by severe shortages in the country's public hospitals.
That was up from 67 percent of medicines and 61 percent of supplies a year ago.
The study, which analyzed more than 240 health centers nationwide, was carried out by a non-profit medical organization and academics at Central University of Venezuela.
It found that 90 percent of hospital emergency services were hit by "periodic failures" and that 70 percent of hospital nutrition programs reported shortages, in a country where food has also grown scarce.
The shortages "explain why there are waiting lists at all the hospitals," said opposition lawmaker Jose Manuel Olivares, who presented the study in congress.
The opposition-held legislature passed a law in April requiring President Nicolas Maduro's leftist government to accept humanitarian aid for the food and medicine shortages.
But the Supreme Court, which the opposition says Maduro controls, ruled the measure unconstitutional.
UN Secretary-General Ban Ki-moon has called the situation in Venezuela a "humanitarian crisis." But Maduro's government rejects the term.
The president blames the shortages hitting the once-booming oil producer on an "economic war" by wealthy elites seeking to destabilize his government.
The opposition says the failure of Maduro's socialist economic model is to blame.