The Swedish prosecutor has cancelled an appointment to interview Julian Assange inside the Ecuadorian embassy in London, according to the WikiLeaks founder.
Mr Assange said the move by Marianne Ny was "reckless".
The activist has been living inside the embassy for almost three years to avoid extradition to Sweden where he is wanted for questioning over sex allegations by two women, which he denies.
He fears that if he goes to Sweden he will be taken on to the United States for questioning over the activities of the whistle-blowing website.
The Swedish authorities have now agreed to travel to London to interview him inside the embassy.
He said: "This afternoon, the Swedish prosecutor Marianne Ny cancelled a prospective appointment to take my statement today. We proposed the dates and Ny accepted them.
"Prosecutor Ny led my lawyers to believe that the appointment was proceeding. My lawyers had booked tickets and I have been put to considerable expense.
"Last year, the Swedish court of appeal found that Prosecutor Ny had breached her duty because she had refused to take my statement for four-and-a-half years.
"The prosecutor waited another seven months before finally accepting my offer to take my statement in London.
"Today I learned that the Swedish legal application to Ecuador, which is likely to take weeks, was only sent to Ecuador two days ago.
"To behave in such a way seems reckless and it is hard to imagine that it was more than a public relations exercise. It is impossible to maintain confidence in this prosecutor under such circumstances."
The Australian entered the embassy three years ago on Friday. He has since been granted political asylum by the government of Ecuador under the 1951 Refugee Convention.
Mr Assange believes he risks extradition to the US from both the UK and Sweden.
Over a period of nearly five years, he has been detained without charge in prison, under house arrest and in the embassy.
His supporters point out he has not seen the sun in three years as the embassy has no outdoor area.
Police have mounted a round the clock guard on the embassy since he took refuge there at a cost believed to be over £11 million.