The sales tax must be restored if Pakatan Harapan is to abolish the Goods and Services Tax (GST), Tun Dr Mahathir Mohamad said.

"GST replaces the sales tax. If we abolish the GST, we must restore the Sales Tax.

"But all processes by the government should be done stage by stage.

"If we suddenly abolish it (GST) and we have no (alternate) source of income, that will be very bad for the government," the former prime minister said.

He said this during the "Insight Talk – Saving Malaysia: Friends and Foes" forum on Facebook Live this morning, where he was a panelist alongside his former foe DAP adviser Lim Kit Siang.

The forum was moderated by veteran journo Jahabar Sadiq.

Dr Mahathir also said, even in the past with petroleum, when the government had to increase petrol price, they did it gradually.

"And this can be reversed, in a way that will not hurt the people and hurt the government's finances,” he said.

Dr Mahathir, who is also Pakatan Harapan chairman, had previously announced that the coalition vows to abolish the GST within 100 days of taking over Putrajaya.