THE HAGUE (AFP) - Dutch prosecutors on Wednesday (Dec 16) said a man had cracked US President Donald Trump's Twitter account in October despite denials from Washington and the company, but added that the so-called "ethical hacker" would not face charges.

The man, named as Victor Gevers in Dutch media, reportedly hacked into Trump's account @realDonaldTrump by guessing his password on Oct 16, Dutch media reports said.

Both the White House and Twitter have strenuously denied reports that the account had been hacked.

Gevers, 44, disclosed the hack immediately, saying the password he guessed was "maga2020!", referring to the Trump slogan "Make America Great Again."

"We believe the hacker has actually penetrated Trump's Twitter account, but has met the criteria that have been developed in case law to go free as an ethical hacker," the public prosecutor's office (OM) said.

It added that hacking was a criminal offence in the Netherlands.

But "special circumstances, also referred to in practice as 'responsible disclosure'," could stop prosecutors from taking steps, the OM added.

Dutch prosecutors made their findings based on an investigation by police's specialist cyber unit called Team High-tech Crime.

"Both the hacker and the American authorities have been informed of the outcome of the investigation," prosecutors said.