Communications and Multimedia Minister Salleh Said Keruak has accused the Swiss attorney- general (AG) of "breaking protocol and circulating misinformation" over its investigations on state-investor 1MDB, according to Britain's the Guardian daily.

“It’s very unusual, and against normal protocol, for a senior official of one country to speak publicly on the internal matters of another country. Yet that is what the Swiss AG has done,” Salleh reportedly told the Guardian in response to a request for assistance from Swiss AG Michael Lauber over its own investigations on alleged misappropriation of 1MDB funds.

In what the daily described as being the most scathing statement on the matter from a Malaysian minister, Salleh also said: "These premature statements appear to have been made without a full and comprehensive appreciation of all the facts.”

Reuters had last Friday reported on the official request from Lauber's office and Deputy Prime Minister Ahmad Zahid Hamidi later opined that it should have been conveyed via government-to-government channels.

Concurring with Zahid, Salleh reportedly told the Guardian that Lauber should have first contacted his counterpart in Malaysia.

“Does the Swiss AG normally talk to the media first, and then the relevant authorities afterwards?” Salleh said in pointing out that 1MDB had undergone extensive audits since 2009 and the US$4 billion figure cited by Lauber “simply could not have been misappropriated under such conditions”.

He also accused Lauber of inferring that the Malaysia had been uncooperative “when in fact Malaysian authorities have been waiting to hear from their Swiss counterparts for many months".

Malaysian AG Mohamed Apandi Ali has agreed to cooperate with the Swiss investigation but insisted this was a separate probe from those under scrutiny by Malaysian Anti Corruption Commission (MACC).

Apandi, based on MACC's investigations, had cleared Prime Minister Najib Abdul Razak of any wrongdoings linked to the RM42 million that SRC International deposited into his personal accounts, as well as the RM2.6 billion donation.

In response to the statements by Zahid and Salleh, spokesman for the Swiss AG's office (OAG) Andre Marty had said the OAG will not issue any comments on political statements.

Marty, however, reportedly told the Nikkei Asian Review yesterday that Najib is not one of those suspected of wrongdoing in the Swiss probe.

This comes after the Swiss OAG revealed it suspected former Malaysian officials and 'persons unknown' were involved in the misappropriation of funds from state-owned firms.

Najib has consistently denied any wrongdoing in these matters.