Commenting on the topic of a referendum which Britain is planning to hold on its EU membership, Hague said Britain's intention is to upgrade the EU and reform it.

As for the referendum, our government can pursue a campaign to stay in the EU, the British official told the commercial television.

Reforms are necessary in order to make the Union competitive in the future, he added.

When you enter the EU, you will have the right to take part in that discussion and join us in Britain in efforts to find ways to adjust the EU to the 21st century, Hague said.

During his visit in Zagreb, he is expected to be received by his Croatian counterpart Vesna Pusic on Thursday evening and by President Ivo Josipovic and other officials on Friday.

Hague confirmed that Britain would impose a temporary ban on the employment of Croatians upon Zagreb's entry into the EU on 1 July.

We will introduce transitional restrictions. We sincerely believe in the free movement of capital and goods and in free movement of labour and people in the EU, but we have the right to transitional restrictions for a few years, he said on this topic, adding that many other EU members would do the same.

As for British investors who are interested in being granted concessions for the seaport of Zadar and who seem to be deterred by uncertainty he said that there was a plan on who would invest, but then such plan was changed.

This can happen everywhere. All of us, including we in Great Britain, must try offer certainty to business people, the British foreign secretary said.

During his recent visit to London, Croatian President Ivo Josipovic said that his country was seeking partners for exploration of oil and gas, and British oil companies are leading in the world.

If they see a chance, they are going to take part in that, Hague said in comment on that topic.

Before coming to Zagreb, Hague is expected to visit Belgrade for talks with Serbian officials on Thursday.