“I read a statement this morning by a PH minister acknowledging that the GST was not the primary reason for the increase in prices,” he said in a Facebook post.

“I was shocked to read this, as prior to the recent general election, the GST was exploited as an issue to paint the previous government in a negative light.

“At that time, they did not accept the government’s explanations. In fact, we were mocked. Now the PH government has to accept reality, in spite of its earlier accusations against the previous administration,” he said.

PH had listed abolishing the GST as one of its election promises ahead of the May 9 polls.

The consumption tax, which was introduced in April 2015, was zero-rated on June 1, with PH saying it would re-introduce the sales and services tax (SST) to partly offset any shortfall in revenue.

Critics of the GST said the tax had led to inflation and higher prices.

However, Najib said the prices of goods did not appear to have gone down after the GST was scrapped.

“Since the prices of goods have not come down, I am worried that when the SST is introduced in September, the prices will increase at a higher rate.”

He added that the higher cost of living would be at odds with what PH promised before the election.

Noting that the previous government had warned the opposition against exploiting the issue, he expressed hope that the PH administration would take steps to address the issue.