ABC reporter Linton Besser and camera operator Louie Eroglu had been due to appear in court this morning after first being told they would likely be charged for obstructing a public servant.
But the ABC said police had called their lawyer last night to say no charges would be filed.
"The lawyer was called in the middle of the night and told it's all off you don't have to go to the court," ABC Southeast Asia correspondent Adam Harvey said.
Besser had questioned Najib as he walked into a mosque in Kuching, Borneo, on Saturday night, asking the prime minister why hundreds of millions of dollars had been deposited into his bank account.
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They were surrounded by Najib's security team but then allowed to leave before being arrested later.
Police questioned the pair for six hours before they were released but ordered not to leave Malaysia awaiting possible charges.
"Malaysian police have indicated this morning they may not press charges against Four Corners journalists Linton Besser and Louie Eroglu," the statement said.
"The situation remains unclear and we are waiting for confirmation," it added.
Foreign Minister Julie Bishop had today expressed concern at their detention
"I'm always concerned when there are instances of a crackdown on freedom of speech -- in democracies particularly," Bishop said while visiting Fiji.
Najib, 62, has been under fire over allegations that billions of dollars were stolen from a state firm he founded and over his own acceptance of a murky $681 million overseas payment.
Media outlets reporting on the allegations have been muzzled and whistle-blowers arrested, raising concerns over rights and freedom of speech.