Maruti's Gurgaon labour union has taken up the cause of for workers arrested two years ago during unrest at the company's Manesar plant which resulted in the death of a senior manager.

The Times of India reported that the incident in  uly 2012 had seen the Haryana government order a probe by a special investigation team even as the company went ahead and sacked nearly 500 of the 1,500 permanent workers at the Manesar plant.

Police also rounded up several workers after the unrest and nearly 150 are still in jail. Kuldeep Jhangu, general secretary of the Maruti Udyog Kamgar Union (MUKU), told the ET that denial of bail is "unjust" and claimed that most of those arrested are innocent.

He said: "Two years have passed since the incident has happened and these workers are still languishing in jail. This is unfair and unjust. Many of them are innocent."

Workers plan a protest rally next Sunday and Jhangu said around 3,000 workers from Maruti Suzuki Gurgaon and Manesar facilities will attend to petition the state government to intervene in the matter.

Jhangu added: "There has not been a proper inquiry into the incident. We want justice for those, who have been arrested, and the least they can get is bail in the intervening period."