"It is new ground, very unusual, it is something we try to avoid," Swedish justice official in charge of the Assange case, Cecilia Riddselius, told The Guardian.
Riddselius explained that the talks would go ahead on Monday because "a decision was taken to actually raise it to the level of the cabinet."
She told the publication that Ann Linde, State secretary to Minister for Home Affairs Anders Ygeman at the Ministry of Justice, would open negotiations on behalf of the Swedish authorities.
Riddselius said that while ministerial non-interference in individual cases is a "strict rule" in the Swedish legal system under normal circumstances, a "political decision" had been made in the Assange case.
"We have agreed to what the Ecuadorians asked for. It was a political decision to have this discussion," she told the daily.
Assange played a key role in uncovering a global surveillance network, in which the communications of high-level politicians, diplomatic missions, businesses and ordinary citizens were intercepted by US and UK intelligence services.