Heartbreaking images were posted online by Mesa de la Unidad Democratica today showing dozens of tiny infants lined up in makeshift cots.
Each is wrapped in a blanket in half a cardboard box with their medical notes sellotaped to the front on a piece of paper.
The party captioned the photos: "So the world knows: In our neonatal units at the Dr Domingo Guzman Lander hospital they are being kept in cardboard boxes due to a lack of incubators. 20 Sept"
Authorities are now investigating the images, which have not been independently verified.
"We in no way justify the actions taken," Venezuelan Social Security Institute President Carlos Rotondaro said on Twitter.