In November a filing error revealed that Mr Assange faced charges in the USA - although it was not clear what those charges were.
Moreno didn't say he would force Assange out, but said Assange's legal team is considering its next steps.
MailOnline has contacted the Home Office for comment.
WikiLeaks has been a focus of special counsel Robert Mueller's investigation of any links between associates of President Donald Trump and Russian efforts to interfere in the 2016 presidential election.
The Ecuadorian president has earlier urged the WikiLeaks founder to give up his asylum at the United Kingdom embassy, but noted that it should happen only after British authorities give guarantees that Assange won't be extradited to the US.
Last month, an inadvertent court filing in a case unrelated to Assange revealed that he has been charged in secret.
Julian Assange speaks to the media from the balcony of the Embassy Of Ecuador on May 19, 2017 in London, England.
Addressing Assange's residency in the embassy, Moreno said: "I do not like the presence of Mr. Assange in the Ecuadorean embassy, but we have been respectful of his human rights and with that respect in mind we think that six years is too long for someone to remain almost incarcerated in an embassy".
Assange has been holed up in the Ecuadorian embassy since 2012, when he was granted asylum while facing allegations of sex crimes in Sweden that he said were a guise to extradite him to the US.
But he said Ecuador was not about to throw Assange out.
Moreno said Assange did not need to fear he would be transferred to a country where he could face the death penalty: "According to the British government, they would never extradite a person to a country where his life is at risk".
Mr Assange founded WikiLeaks in 2006.
"He will spend a few months in jail, after that, freedom", Moreno said.
Mr Moreno said today that Mr Assange still faces jail time in Britain for violating bail terms when he sought sanctuary to avoid extradition to Sweden so authorities could quiz him as part of a sexual assault investigation.