Ecuadorean government documents have laid bare an unorthodox attempt to extricate WikiLeaks founder Julian Assange from his embassy hideaway in London by naming him as a diplomat to Moscow.

The files made public late on Tuesday by Ecuadorean opposition lawmaker Paola Vintimilla largely corroborate a recent Guardian newspaper report that Ecuador attempted the manoeuvre late last year.

READ MORE Julian Assange told to curb speech, tend to cat

Russian diplomats called the story "fake news," but the files show Assange was briefly named "political counsellor" to the Ecuadorean Embassy in Moscow.

The plan appears to have fallen apart when Britain vetoed Assange's diplomatic status.

A letter dated December 21, 2017 from Britain's Foreign Office says UK officials "do not consider Mr Julian Assange to be an acceptable member of the mission."

WikiLeaks, the Russian Embassy and the Foreign Office did not immediately return messages.