The majority of offshore workers believe health-and-safety standards have dropped in the last six months, according to a survey.
The Unite union wants a confidential whistle-blowing helpline to be set up where workers can raise concerns.
A survey carried out by the union found 58% of those who work at sea said standards have dropped, with 38% concluding they had stayed the same and the remainder saying improvements have been made.
Just over a third of workers said they felt they were unable to report concerns due to fears of victimisation.
Around 780 employees took part in the survey during October and November, with 93% of them Unite members.
Unite regional officer William Wallace said: "Companies should never make cuts that threaten health and safety and put the lives of our members at risk. The lessons of Piper Alpha should never be forgotten.
"We will be calling on the industry to work with health and safety bodies, with the trade unions, and with government so that we can get a confidential helpline created.
"No worker should feel victimised for raising these issues. The consequences could be catastrophic."
It was also revealed that 82% of the survey participants had seen a reduction of skilled personnel which has effected productivity and task performance in the workplace.
Mr Wallace added: "Unite knows that North Sea operators are facing challenges due to falling oil prices but companies have to realise that they can't prop up their profits - or create a sustainable industry - by simply reducing the numbers of skilled workers on the job."