Thousands of workers have marched on Queensland parliament demanding workplace safety action after a colleague's death.
Construction, Forestry and Maritime Employees Union (CFMEU) members downed tools on Thursday, convening in the Brisbane CBD before sending a message to state parliament.
About 6500 chanted "stand up, fight back", calling for greater protections for outdoor and high-risk site workers.
They have demanded a heat stress code of practice following the death of Daniel Sa'u in December.
The union said Mr Sa'u was found deceased in his car after leaving a Cross River Rail site in Salisbury on December 28, alleging he had symptoms of heat stroke.
A Cross River Rail authority spokesperson said on Thursday the health and safety of the project's workforce was taken extremely seriously and it expected the site's major contractors to uphold the highest safety standards.
Transport Minister Bart Mellish said he had made it clear that the highest safety standards were to be upheld at all worksites.
Contractors group CPB offered their condolences to Mr Sa'u's family and friends but said it wouldn't be appropriate to comment as they had not been advised of the circumstances by authorities.
CPB said they stood "committed to the health and wellbeing of our people, and everyone working on our construction projects".
Mr Sa'u's wife Jeraldine addressed the crowd on Thursday flanked by family, calling for workplace safety action.
"That's what's motivating us to be here today, for the union and the workers as well," she said.
"It's an unbearable feeling ... we were never prepared for this."
Mr Sa'u's mother Segia said her son called her the morning of December 28 before indicating he'd call her back after his shift.
"I waited for the call," she said, fighting through tears.
"About nine o'clock at night we heard on the news .... I couldn't believe it."
The CFMEU was set to present three resolutions to Premier Steven Miles on Thursday.
"Queensland workers condemn the government for selling out on workers' safety," CFMEU state secretary Michael Ravbar said.
"Workers further censure the minister for industrial relations, Grace Grace, for overseeing the dysfunction within the state regulator."
Mr Ravbar then called for Ms Grace's resignation.
He said a designed and implemented heat stroke code of practice for high-risk workers was necessary.
"This will be a test of the leadership of Steven Miles," Mr Ravbar said.
