NEW visa regulations in the European Community could lock Hong Kong residents outside the doors of a ''Fortress Europe'', legislators have warned. They want the British Government to safeguard the travel freedom of Hong Kong residents in Europe. Nine EC countries, not including Britain, are planning to set up a Common Visa Area from October so that one visa instead of nine would be needed for entry by tourists. Councillors fear that could mean an end to visa-free travel in six of the countries. Legislator Emily Lau Wai-hing, convenor of the Legislative Council's sub-committee on nationality, was prepared to call a meeting next week of government officials and representatives from European consulates. She called the proposal a ''Fortress Europe policy'' that could make entry for Hong Kong residents more difficult. She urged the consulates to exempt Hong Kong from the policy. Howard Young pointed out that while all nine countries required visas for Hong Kong Certificate of Identity holders, six of those countries granted visa-free entry to holders of the British National (Overseas) passport and British Dependent Territory Citizen passport. ''It would be a detrimental step if an exercise which was meant to simplify and ease travel meant some people faced new inconveniences,'' he said. Mr Young, the legislator representing the tourist industry, said countries that offered visa-free privileges ought to take steps to maintain such arrangements. A government spokesman said the British and Hong Kong Governments had approached the other countries to ensure that Hong Kong residents could continue to enjoy the visa-free facilities offered by Spain, Belgium, Luxembourg, the Netherlands, Italy and Greece. They would ask the other three countries - Portugal, France and Germany - to lift visa requirements.