The pressure tactics may include demand by the Left parties for adjournment of Parliament's regular business to take up the issue.
The trade unions may also approach the court challenging the Maruti Suzuki India (MSI)'s decision to terminate 500 permanent workers.
Major central trade unions, including CPI-affiliated All India Trade Union Congress (AITUC) and CPI(M)-affiliated Centre of Indian Trade Unions (CITU), will meet on August 21 to finalise a rally in the National Capital to press for their demands.
"We do not expect any positive response from the Haryana government. We are planning to take it to the national level and pressurise the central government. The Left parties, along with other like minded parties, will press for an adjournment in Parliament," AITUC National Secretary DL Sachdev told PTI.
MSI, he said, cannot take such a major decision without consulting the state government. CPI(M) Rajya Sabha Member Tapan Kumar Sen had last week raised the issue in the house terming removal of workers "vindictive and retaliatory". JMM MP Sanjiv Kumar had demanded a CBI probe into the violence.