Unison, which has more than 1.3 million members according to its website, said the most pressing issue for new Prime Minister Rishi Sunak and Health Secretary Steve Barclay was "without doubt finding a solution to the many problems affecting the NHS", Reuters reported.
"The NHS is losing experienced staff at alarming rates. Health workers are leaving for work that pays better and doesn't take such a toll on them and their families," Unison General Secretary Christina McAnea said in a statement.
"If this continues, the health service will never conquer the backlog and treat the millions desperately awaiting care."