HSE figures show that the number of non-fatal injuries per 100,000 workers rose from 359 in 2017/18 to 366 in 2018/19.
During the same period there was a 22% decrease in the number of construction prosecutions undertaken by the HSE, falling from 202 in 2017/18 to 158 in 2018/19.
On the positive side construction fatalities in 2018/19 were a new record low, at 30.
Unite national officer Jerry Swain said: “These figures are deeply worrying. While of course we welcome that the number of deaths has decreased, this has to be tempered with the fact that construction injuries have gone up.
“The increase in injuries is likely to in part be a result of employers failing to comply with safety laws. Unite firmly believes that a major contributory factor to this is the sharp decline in prosecutions, which clearly indicate that the HSE’s enforcement activities are decreasing.
“This is a dangerous cocktail and it will likely to result in a greater number of workers being injured and possibly killed unless urgent action is taken to reverse this trend.
“Too many employers in construction remain prepared to ignore safety laws, to boost profits, as they believe that they won’t be caught.
“These figures show the importance of having a strong, active and interventionist HSE.
“The Conservative government’s swingeing cuts to the HSE are now resulting in workers paying for the decrease in enforcement with their health.”