The employees unions of Hindustan Petroleum and Bharat Petroleum said on Tuesday that they will strike work for three days starting March 25 in protest against the proposed privatisation of two oil majors.

"Even after these three days, if the government does not stop the privatisation process, employees unions and officers association may resort to indefinite strike", Oil Sector Officers' Association convenor Ashok Singh said in a statement in Mumbai.

He said the views of the association have "not only been endorsed" but also been "strongly" supported by Union Petroleum Minister Ram Naik, the Parliamentary Standing Committee on Petroleum and Chemicals, and the entire Opposition.

"Under these circumstances, since the government is proceeding with the privatisation, the association is left with no option but to resort to agitations like wearing black badges, work to rule and complete strike from March 25 to 27", he said.

Several legal luminaries have also suggested that parliamentary approval was mandatory before undertaking any privatisation of HPCL, which was created by an Act of Parliament, it added.