Police officers have been stationed outside the embassy around the clock since last June.
Assange, who is fighting extradition to Sweden on sex charges, which he denies, has been granted political asylum by Ecuador.
Assange fears that Sweden would extradite him to the United States.
A spokesman at the Ecuadorian embassy said that "the Ecuadorian government is concerned by the significant cost to the taxpayers of London of policing the embassy."
The statement continued: "However, we believe this expenditure could be avoided if the UK government would provide the undertakings that the Ecuadorian government has sought that there will be no onward extradition of Julian Assange to the United States."