James Dauris said he had spoken to Chief Justice Abdulla Saeed, whose signature was on a verdict saying that nine prisoners should be freed until they could have fair trials.
The ruling has triggered a crisis – including an extraordinary standoff between the government and judiciary – that shows no sign of being resolved.
“He said that neither his nor any other judge’s signature was forged. He told me about the great pressure judges are under,” said Dauris.
“It is in the fundamental interest of every Maldivian that the independence of the judiciary is respected and supported.”
Dauris retweeted the forgery allegation, which came from a ruling party MP.
US ambassador to the Maldives Atul Keshap also expressed his concern about threats to the judiciary.
Crowds gathered outside Saaed’s house late on Saturday as speculation mounted that he was going to be arrested but police denied the rumour on Twitter. They are, however, investigating bribery allegations involving him and another Supreme Court judge, Ali Hameed Mohamed.
There are no signs of the government releasing the prisoners and neither opposition leader Gasim Ibrahim nor former president Mohamed Nasheed, who are in exile and two of the nine individuals named in the verdict, have returned to the Maldives.
The Supreme Court has said there is no legal obstacle preventing the Prosecutor General’s office from starting retrial proceedings.
In a separate development, two politicians wanted in connection with a bribery case and who were arrested at the airport upon their return to the Maldives after months in exile were freed. The judge said their detention was politically motivated.