The Delhi unit president said that the Congress would not participate in the special meeting in the Central Hall of Parliament to introduce GST at midnight on June 30.
"GST in its present format will not only ruin small and mid-size businessmen, it will also create large-scale unemployment," Maken said in a press conference at the Delhi Congress office here today.
The party will back the Delhi Bandh call given by traders in protest against the introduction of the new tax, he has said.
"For an uncomplicated taxation system, the tax slabs under GST should not have been more than two. Many countries, such as Malaysia and Singapore, are operating under a reduced, single taxation system of GST," he said.
He attacked the BJP led National Democratic Alliance (NDA) government, saying it was "ill-prepared" to implement the new tax even though it was being launched "grandly".
The Delhi Congress would hold district-level protests against GST in the coming days, he added.