Malaysian PM not accused of corruption

Malaysian Prime Minister Najib Razak is not among those accused of wrongdoing in an investigation by Switzerland's chief prosecutor into alleged corruption involving the 1Malaysia Development Berhad (1MDB) sovereign fund, a Swiss official says.

The Swiss Attorney General's office said last Friday that it had identified four cases of alleged criminal misconduct in the suspected misappropriation of about $US4 billion ($A5.68 billion) from Malaysian state companies.

Andre Marty, spokesman for the Office of Swiss Attorney General Michael Lauber, said in an emailed response to a Reuters query on Tuesday: "In the ongoing criminal proceeding of the OAG (Office of Attorney General), Mr Najib Razak is not one of the public officials under accusation."

Lauber's office announced in last August that it had opened criminal proceedings related to 1MDB, whose advisory board is chaired by Najib.

Late last week, Lauber's office issued a statement in which it said it had formally asked the Attorney General of Malaysia for assistance in Switzerland's investigation.

It said the investigation related to possible bribery of foreign public officials, misconduct in public office, money laundering and criminal mismanagement and that the criminal investigation involved two unnamed "former officials" of 1MDB and "persons unknown".

The statement came days after Malaysia's attorney general cleared Najib of any criminal offences or corruption, declaring that $US681 million deposited into his personal bank account was a gift from Saudi Arabia's Royal Family.

Najib has consistently denied wrongdoing, and said the funds were a political donation and he did not take any money for personal gain.

The Malaysian Attorney General's office said on Saturday that it would take all possible steps to follow up and collaborate with its Swiss counterpart, but said the investigations into donations made to Najib were entirely separate from those into 1MDB.