The Employers and Manufacturers Association says it wants National to implement employment law changes to help put all employees on a more even playing field.
Prime Minister John Key says National will campaign on making the labour market more flexible, and would bring in changes unions will not like if the party was re-elected in November.
The association's industrial advisor, David Lowe, told Morning Report businesses are looking for changes on collective bargaining.
Mr Lowe says at present employers have to treat employees belonging to a union differently to those who do not, but they want to be able to treat all employees the same.
Council of Trade Unions secretary Peter Conway said this Government favours individual bargaining which puts the employee at a disadvantage.
He said that not all flexibility is bad in a workplace but the sort of flexibility National is usually talking about is to tilt the balance in favour of the employer and put the worker in a vulnerable bargaining position.
Mr Conway says the CTU wants more industry-level bargaining and a rise in the minimum wage.