The Public Accounts Committee (PAC) has called up former prime minister Najib Abdul Razak to provide his explanation regarding the purportedly missing GST refunds amounting to RM19.248 billion, as claimed by Putrajaya.

In a statement, PAC chairperson Ronald Kiandee said the former finance minister is slated to appear before the committee on Oct 17, for the latter to "provide his explanation and statement".

Aside from Najib, Kiandee said the committee will also summon Finance Minister Lim Guan Eng later next month, as well as former Treasury secretary-general Irwan Serigar Abdullah.

"...The PAC has unanimously decided to recall Irwan on Oct 16, even though he has already been present and had given his statement to the committee on Sept 13.

"At the same time, the PAC has also set Oct 22 for Lim to give his explanation and statement on the same issue," the statement read.

The PAC probe is in relation to Lim telling the Dewan Rakyat in August that a Customs Department audit had revealed that the total GST refunds amount to a mere RM148.6 million, from the date of its implementation until May 31, 2018.

Lim had initially stated the bulk of the RM18 billion sum was unaccounted for and had been "misused" by the previous administration.

He later amended the shortfall to RM19.248 billion, attributing the mistake to a decimal error made by an official of his ministry.

Johari: Impossible that funds missing

As part of the PAC’s probe, former second finance minister Johari Abdul Ghani was summoned yesterday to explain the RM19.248 billion claim and he had denied that any of the GST funds were missing.

"It is impossible for the funds to have gone missing and I have explained the matter to them (the PAC)," Johari said in a statement after being questioned.

He explained that there are various categories to the GST refunds, including refunds which could not be paid out as investigations are still ongoing for certain claims that had been made.

Former deputy finance minister Ahmad Husni Hanadzlah was also questioned by the PAC yesterday.

Johari was appointed Second Finance Minister on June 27, 2016, replacing Husni who had resigned from the post which he held since April 2009.