Prime Minister John Key recently visited the EU to start the talks and Mr Sinclair said Great Britain was proving to be a ''smart friend'' in its support.
''This is a major win and a long time coming.''
The agreement to start negotiations on the free trade agreement came after election of a new European commission which had adopted a pro liberalisation agenda for trade, Mr Sinclair said in an interview.
There were some areas in Europe yet to be finalised, including a single digital European market, a single energy market and the finalisation of large trade deals with America and Japan.
The EU was preparing to negotiate free trade agreements with New Zealand, Australia, the Philippines and Indonesia.
''Our hope is the New Zealand deal will advance as quickly as possible.''
However, before the process started, there would be public consultation, a regulatory impact assessment and a sustainability impact on things like climate and the environment.
Provided those passed inspection, talks could begin at the end of next year or, more likely, early 2017, and be concluded in the term of the current commission which ended in 2019, Mr Sinclair said.
The American trade deal had been negotiated over 12 years.
Mr Sinclair and the commission were working with the Government to attract greater British investment into New Zealand. New Zealand companies were already operating successfully in the UK.
With the recent re release of the Government's business growth agenda, some ambitious export targets were being set, he said.
''To achieve those export targets, companies needed to build capital and that required foreign direct investment.''
New Zealand's total foreign direct investment figures were: Australia ($110 billion); the UK ($53 billion); the US ($33 billion); and Japan ($8 billion).
