Sham industrial arrangements that involve a handful of employees being asked to sign a "collective" agreement on wages and conditions on behalf of hundreds of other employees could be outlawed by Labor.
Labor's spokesman on employment Brendan O'Connor said if elected, a future Labor government would introduce laws to ensure that collective bargaining was not undermined by sham agreements.
Mr O'Connor said some employers were getting away with using a small cohort of employees to vote up inferior enterprise agreements, which were then used to reduce the pay and conditions of other much larger and often very different workforces.
Private contractors building the Sydney Metro Northwest have been accused of trying to slash the pay and conditions of skilled tradespeople using a controversial pay agreement like the one Carlton United Breweries used to slash worker salaries.
"Labor believes that collective bargaining should not be able to be undermined by these sham collective agreements, often referred to as no-stake agreements," Mr O'Connor said.
"Labor will legislate to make clear that the workers who vote on an agreement must be broadly representative of the workers who may ultimately be covered by the agreement."
Under the proposed laws, it would not be possible to use a wages agreement signed by workers in one workplace to cover people employed in different locations.
"It will no longer be possible to have short-term casual workers reach agreement on terms that bind permanent workers," Mr O'Connor said.
"Labor will also change the law so that workers and their unions can apply to the Fair Work Commission to re-negotiate sham enterprise agreements."
"Australians deserve a government that understands that the challenges in Australia's labour market and workplaces are real and puts people's wellbeing above corporate profits."
The Australian Council of Trade Unions welcomed the announcement which would apply to a tactic used by Carlton United Breweries, which used enterprise agreements signed by a small number of workers often disconnected from the workplace the agreements covered. It said CUB forced maintenance workers onto an enterprise agreement signed by three workers in an office in Perth.
"We need to change the rules to restore balance to the bargaining process, and this is a welcome commitment from the ALP," ???ACTU president Ged Kearney said.
"The use of these sham agreements have become a massive problem.
"The Turnbull Government has cut pay for low-paid workers, while refusing to address casualisation, underemployment, unemployment, sham contracting, improper use of ABNs, labour hire, stagnant wage growth and a minimum wage which leaves full time workers in poverty."
