It slammed the charges to be made against Najib as "politically motivated and the result of political vengeance" by new Prime Minister Mahathir Mohamad.
Najib has denied wrongdoing since news of the scandal emerged. He pleaded not guilty to all charges. "No doubt, there will be more IPs".
Prior to this, it was not known who will represent Najib who has already parted ways with two separate legal teams.
The patrician and luxury-loving Najib, wearing a suit and a red tie, appeared calm and smiled as he was escorted into the court complex.
Mahathir, 92, said in an interview with Reuters last month that embezzlement and bribery with government money were among the charges that Malaysia was looking to bring against Najib, 64, adding they had "an nearly ideal case" against him.
Najib pleaded not guilty, but the charges, the first of their kind faced by a Malaysian premier, and his court appearance were the culmination of a swift and stunning downfall for the man who led the country for almost a decade.
Three of his children - Ashman, Nooryana Najwa and Nazifuddin - watched the proceedings in the packed court. "Only merits of SRC International and this case is under the interim gag order which is until August 8", he added.
"I claim trial", he said in court on Tuesday before being granted bail at 1 million ringgit ($250,000) in cash.
Son-in-law Daniyar Kessibayev, who is from Kazakhstan, and Datuk Mohd Nazifuddin Mohd Najib, the former prime minister's son from his first marriage, were also present.
Najib, who lost power in a May election, was arrested by anti-corruption officers on Tuesday afternoon and will be charged on Wednesday morning.
A new investigation began after his shock election loss in May.
Najib entered parliament at 23 and attained the top job in 2009, setting up 1MDB shortly after, but his second term in office was plagued by allegations about the fund. The sum is just a fraction of the billions of dollars allegedly siphoned from 1MDB in a scandal that has dogged Najib's leadership for years and is what many say led to his stunning defeat on May 9. Sources close to the matter said he may face several charges.
After a night in lock up, the 64-year-old was formally charged with embezzlement and bribery with government money in a Kuala Lumpur court.
When asked about the commotion at the court lobby as he was about to talk to reporters, Thomas said he was surprised as he was only expecting to answer questions from the media. He left as chants of "Melayu" resounded, a seeming insistence that he speak in the Malay language.
Najib was granted bail set at 1 million ringgit ($247,000).
"Today, I have been officially charged". "There were some witnesses who disappeared, ran overseas", and some were clearly told by officials from other government agencies to do so, said the Macc official.
"I believe in my innocence and this is the best chance to clear my name", he said, waving off questions with a smile.