G9 was set up in 2010 by nine offshore wind project developers, including Danish firm Dong Energy, UK-based Centrica and Sweden's Vattenfall, to improve health and safety in the offshore industry.
The group's annual incident report shows that across 45 sites in Europe, 959 incidents were reported in 2014, compared to 616 a year earlier. The figures were compiled in association with the Energy Institute.
The increase is partly because more projects are involved in the study - only 35 sites took part in 2013. But, an Energy Institute spokesperson said: "Unfortunately there is no straight answer to explain the increase. There are a larger number of sites being reported than last year, and some will be at different stages of development which may have higher risk, ie construction."
The biggest increase was the number of "near hits" reported which leapt from 345 in 2013 to 655 this year - a 90% increase. Most of these occurred on the turbine or during onshore activities. G9 defines "near hit" as "any incident that could have resulted in a work-related accident but did not, either by chance or timely intervention".
There was also an increase of 64% year on year in the number of incidents that did need first aid or medical treatment. This year, 149 cases were reported, 15.5% of the total number of incidents. This compares with 91 incidents in 2013, making up 14.8% of the total incidents reported.
Encouragingly, however, for the second year running there were zero fatalities in the offshore wind industry and work days lost due to incidents fell by 33% to 44 days.