Mr Assange, who is seeking to avoid extradition to Sweden for questioning over sex crimes allegations, has been sheltering inside Ecuador's embassy in London beyond the reach of British police since June 19.
Ecuador has granted Mr Assange asylum, but he will be arrested if he steps foot outside the small, central London mission.
Mr Hague told lawmakers on Tuesday that talks are continuing.
Mr Assange claims the Swedish sex case is part of a plot to make him stand trial in the United States over his work with WikiLeaks, which has published large troves of secret US documents. Sweden and Washington reject the claim.