The contentious goods and services tax (GST) was mooted way back in 1984, but the federal government at the time didn't have the "political courage" to do it, said Prime Minister Najib Abdul Razak.

During a question and answer session at the launch of the National Transformation Plan (NTP) annual report today, Najib said GST was a right decision, but it came with a political cost.

"(My administration was) willing to bear the political costs because it is the right thing to do. GST will benefit the rakyat and the country.

"I am convinced (of this)," said Najib, in responding to questions from NTP advisor Idris Jala.