By Andreas Rinke

SEEON, Germany (Reuters) - Britain lacks experience in international negotiations due to its long membership of the European Union and this can slow talks, the prime minister of non-EU Norway told Reuters, adding that she feared "a very hard Brexit".

British Prime Minister Theresa May intends to launch by the end of March the two-year process of negotiating to leave the EU. They are expected to be some of the most complicated international talks Britain has engaged in since World War Two.

Norwegian Prime Minister Erna Solberg said she hoped Britain would be able to negotiate an agreement that keeps it very close to the EU but said it would be a difficult task.

"And we do feel that sometimes when we are discussing with Britain, that their speed is limited by the fact that it is such a long time since they have negotiated" alone on such issues, she said in an interview late on Wednesday while attending a meeting of the Bavarian Christian Social Union (CSU)in southern Germany.

"I fear a very hard Brexit but I hope we will find a better solution," she added.

Though not in the EU, Norway is a member of the bloc's single market and allows free movement for EU workers. It also contributes to the EU budget and participates in Europe's open-border Schengen agreement.

Some Britons favor a Norway-style close relationship with the EU after Brexit. Others argue for a 'hard Brexit' that would take Britain out of both the single market and the bloc's customs union. Britain has never joined the Schengen scheme.

Prime Minister May has so far said little publicly about her negotiating position, arguing that to do so would weaken London's hand in the talks.

In a move that highlighted tensions at the heart of the British government over how to handle Brexit, Britain's ambassador to the EU, Ivan Rogers, resigned this week. In his letter of resignation he also referred to a lack of negotiating experience within the British civil service.

"Serious multilateral negotiating experience is in short supply in Whitehall, and that is not the case in the (European) Commission or in the (European) Council," he wrote.

The Commission in Brussels handles trade and some other negotiations on behalf of the EU's member states. Britain joined the bloc in 1973.

Solberg said it would be very hard for Britain to accept the EU's "four freedoms" - of movement of goods, capital, people, and services - without having a vote in the EU Council.

"I hope that we will find a solution that leaves Britain as a partner in a lot of the European activities that we need them to be a partner in," the Norwegian leader added.

(Reporting by Andreas Rinke; Writing by Paul Carrel; Editing by Gareth Jones)