Malaysia will reopen an investigation into the murder of a Mongolian model in 2006, the Star newspaper reported on its website

Former Malaysian prime minister Najib Razak says he shouldn't be blamed for the multi-billion-dollar 1MDB scandal, and declares he knows nothing about money from the state fund appearing in his personal account.

Mahathir Mohamad told Reuters in an interview that Malaysian investigators already "have an almost perfect case" against the principal suspects who had defrauded 1MDB.

The wife of Malaysia's ousted prime minister Najib Razak on Tuesday arrived at the nation's anti-corruption agency for questioning over a massive financial scandal involving a state sovereign wealth fund.

Former opposition leader Anwar Ibrahim slammed Canberra's "tainted" policy towards ousted prime minister Najib Razak's administration, which was sensationally ousted in last month's election.

Mahathir, who won a surprise election victory this month against Najib Razak's long-ruling coalition, is seeking to repair the country's finances.

Najib Razak's coalition suffered a defeat at the May 9 poll, beaten by a reformist alliance led by Mahathir Mohamad, which broke their six-decade stranglehold on power.

Rosmah Mansor, who is widely reviled for her reported luxurious tastes, issued a statement lashing out at the police raids, complaining that news of them amounted to a "premature public trial".

Clare Rewcastle-Brown, editor of news website Sarawak Report, published details of the alleged transfer of $681mn from 1Malaysia Development Berhad (1MDB) to bank accounts held by Najib.

Police have been searching Najib's home and other places linked to him as part of an investigation into the scandal-plagued state fund 1Malaysia Development Berhad (1MDB).

Police arriving in a dozen vehicles converged on the home of corruption-tainted Najib Razak in Kuala Lumpur beginning late on Wednesday, drawing crowds of journalists and onlookers.

The question for Malaysia now is how Anwar Ibrahim will get along with Prime Minister Mahathir Mohamad, his ally-turned-foe-turned-ally, and what role he will play in government.