The General Workers' Union and the Union Ħaddiema Magħqudin have called for stricter enforcement at the workplace following two construction site accidents this week, one of them fatal.
Representatives of the two unions said there needed to be more inspections and better education.
GWU general secretary Tony Zarb also appealed for more construction workers to become unionised, partly placing the blame for accidents in this category on the fact that many are not protected by unions.
The first accident took place on Monday, when a builder working in a derelict block of flats in Ġużè Howard Street, Sliema, fell off a plank and plunged onto debris below.
Although eyewitnesses said he was bleeding badly, sources said he sustained broken ribs and legs and was recovering at Mater Dei Hospital.
However, the man involved in the second accident on Wednesday was not so lucky.
The part-time builder, working on the first floor of a construction site in Carmel Street, St Julians, went to fetch a tool when he lost his balance, sources said.
As he was falling he tried to grab hold of a brick wall, which gave way.
An autopsy found that the builder did not die from the fall but due to injuries caused by the falling bricks, which killed him instantly.
Reacting to the two accidents, UĦM president Gejtu Tanti said the most effective way to raise awareness was through an education campaign.
"Fines for breaking health and safety regulations must also be increased to discourage employers from failure to enforce them and employees from not obeying them," he said.
Mr Tanti said more inspectors should be employed at the Occupational Health and Safety Authority.
"Although more have in fact been employed, most of whom are better qualified, they still cannot keep up with the increase in construction," he said.
Similarly, Mr Zarb called for more inspections to be carried out at workplaces.
The Occupational Health and Safety Authority said it is investigating both accidents but could not comment any further because of the ongoing magisterial inquiries.