Najiib plead not guilty to the charges and has consistenly claimed no wrongdoing in relation to the 1MDB scandal.
Najib is the first Malaysian prime minister to have been charged in court.
On July 4, Najib pleaded not guilty in the High Court to three counts of criminal breach of trust (CBT) and one charge of abuse of power involving RM42 million belonging to SRC International Sdn Bhd.
The charges - which Najib denies - relate to three transfers totalling 42m ringgit (US$10m) into his bank accounts from SRC International, a former unit of the 1MDB fund that USA investigators say was looted of billions by Najib's associates.
The 65-year-old, who is free on bail, has denied all the charges.
Malaysia´s new government is probing allegations that billions of dollars were looted from state fund 1MDB, which was set up and overseen by Najib, in an audacious fraud that spanned the globe.
If convicted of the charges, Najib faces up to 15 years in jail and a sizeable fine.
Najib spoke softly as he entered his plea in the High Court.
Former Prime Minister Najib Razak talks to a member of the Malaysian parliament
The amended criminal breach of trust and power abuse charges were then read out afresh to Najib before High Court judge Mohd Nazlan Mohd Ghazali.
Allegations of massive corruption were a major factor behind the electoral quake in May that toppled Najib's long-ruling coalition and ushered in a reformist alliance headed by his 93-year-old former mentor Mahathir Mohamad.
His is accused of having received 42m ringgit ($10m; £8m) from state fund 1MDB in his personal bank account. It added that the additional charges have been approved by the Attorney-General.
The US Department of Justice, which is seeking to recover items allegedly bought with stolen 1MDB cash in America, estimates that $4.5 billion in total was looted from the fund.
Police also seized jewellery and valuables valued at more than 1.1 billion ringgit (£208m) from properties linked to Mr Najib.
He appeared at the MACC office in Kuala Lumpur on Tuesday after he was summoned by the anti-graft agency.
The new government reopened the investigations stifled under Najib's rule and barred him and his wife from leaving the country.
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