In an intervention that delighted Brexiteers, Erna Solberg said any attempt by the UK to adopt the so-called “Norway option” was likely to prove “a little bit difficult”.
The EEA is a trade bloc allowing access to the EU single market.
Ms Solberg’s remarks during a visit by Prime Minister Theresa May to Oslo were seen at Westminster as a diplomatic warning that any application by Britain to join Norway in the EEA would be rejected by the trade bloc’s existing members.
Mrs May agreed that the Norway option was not right for the UK.
She said: “The existing relationship that Norway has with the EU is one that has elements that wouldn’t deliver on that vote of the British people.”
Mrs May said she wanted a “good” deal with the EU that took in economic activity and security.
Former Tory minister Nicholas Boles is among a group of MPs campaigning for Britain to adopt a “Norway-style” deal temporarily after Brexit, while the Government spends more years negotiating a long-term trade deal with Brussels.
Mr Boles said: “This is obviously disappointing.”
But Eurosceptic Tories insist that the proposal would tie Britain to Brussels indefinitely, forcing free movement for EU citizens.
Leading Leave campaigner, Tory MP Peter Bone, said: “We cannot have the Norway option as a transition to something else.
“It is simply a non-starter. What we need is a comprehensive free-trade deal similar to the one the EU has with Canada.
“And if we cannot get that, we need to trade with the EU on World Trade Organisation terms.”
The prime ministers yesterday agreed a deal for Britons in Norway and Norwegians in Britain to have the right to remain after Brexit.