In a statement, The European Commission said the plan is due to "the exceptional technical implementation challenges faced by regulators and market participants".
It has therefore granted national competent authorities and market participants one additional year to comply with the rules, pushing the new deadline back to 3 January 2018.
MiFID, covering securities markets, investment firms and intermediaries, was created in response to the financial crisis to help forge a more competitive and integrated EU financial market. However, the Commission says that recent events and market developments have demonstrated weaknesses in some of its underlying principles, and highlighted areas in need of reinforcement or revision.
The reason for the extension lies in the "complex technical infrastructure that needs to be set up for the MiFID II package to work effectively", according to the Commission's statement.
The European Securities and Markets Authority has to collect data from about 300 trading venues on about 15 million financial instruments. However, the European Commission was informed by ESMA that neither competent authorities, nor market participants, would have the necessary systems ready by 3 January 2017.
The FCA was due to issue its Mifid II policy statement in June.
Jonathan Hill, Commissioner for Financial Services, Financial Stability and Capital Markets Union, said:
"Given the complexity of the technical challenges highlighted by ESMA, it makes sense to extend the deadline for MiFID II. We will therefore give people another year to prepare properly and make the necessary changes to their systems. Meanwhile, we are pressing ahead with the level II legislation to implement MiFID II and expect to announce those measures shortly."
