The SJM also accused the government of acting in haste in the matter.
It demanded a white paper detailing the benefits and drawbacks of FDI and said a commission comprising stakeholders should first be set up to examine the issue.
The Manch said that government's 'Make in India' initiative should be more of 'Made by India'.
"SJM believes that the present decision of the government to ease FDI norms for major sectors of the economy has been taken in a hurried manner and without going into the pros and cons of the decision.
Also Read
"It is painful to see that the present government continues to follow the policy of previous UPA government in this regard.
"SJM reiterates its demand for a white paper and urges the government to share the factual position with the people of India instead of repeating mere claims and intention," he said.
The opposition from SJM came three days after another RSS affiliate, Bharatiya Mazdoor Sangh, warned the government of mass agitations if the FDI decision was not immediately rolled back.
Arguing that the government has been advocating liberal FDI regime under its plans to revive manufacturing sector in the country in the name and style of Make-in-India slogan, the Manch said, "Government's endeavour towards Make-in-India should be more of Made-by-India."
Mahajan said it was an established fact supported by empirical data that FDI is not a panacea for all ills.
"In 2014-15 alone, while there has been FDI inflow of USD 31 billion, there has been an outflow of USD 36.5 billion," he said.
The SJM also contested the government's argument that FDI would bring growth and create employment in the country.
"Government has been advocating liberal FDI regime under its plans to revive manufacturing sector in the country in the name and style of Make-in-India slogan," Mahajan said.