The CFMEU and Victorian Labor have reversed their opposition to mandatory drug testing on construction sites after growing problems with the drug ice.
The CFMEU has announced it supports mandatory drug testing, despite opposing the previous government's mandatory testing code just last year. Labor scrapped the code - but has welcomed the agreement between the CFMEU and employers.
The CFMEU's policy supports mandatory saliva testing for drugs for all people on a construction site - including employers, construction workers, crane drivers and tradesmen.
Mr Andrews said the previous government's code was scrapped because it was unlawful and ideologically driven.
"(This is) co-operation that's about outcomes, not about ideology, not about using codes as a political weapon," Mr Andrews told reporters.
"I think it's a very, very good outcome."
CFMEU national construction secretary Dave Noonan said the drug ice posed a threat on worksites not seen for other recreational drugs.
"We have opposed mandatory testing in the past but ... when circumstances change it is reasonable for people to change their mind," Mr Noonan told ABC radio.
"The emergence of ice has caused us to have a serious discussion about the way forward."
Mr Noonan said the union had anecdotal reports of worksite accidents where ice could be a factor, with a near-miss involving a large crane the final straw. Opposition industrial relations spokesman Robert Clark said the move was an embarrassment for Labor after it opposed the mandatory drug testing laws in opposition.
Mr Andrews said plans to breath-test test MPs in parliament house during sitting weeks were still underway, and would go to a Parliamentary Committee for scrutiny.