OSLO- Norway's regulations allowing oil and gas companies to claim refunds for exploration spending do not constitute state aid, the European Free Trade Association Surveillance Authority (ESA) said on Wednesday.

"Having scrutinised it on the basis of a comprehensive complaint, ESA is satisfied that this tax rule does not entail state aid," ESA President Bente Angell-Hansen said in an emailed statement.

The case was brought to ESA by Bellona, an environmental non-profit organisation seeking to block oil firms' access to cash refunds, which have fueled a boom in Norway's petroleum exploration.

"ESA has now concluded that the measure is not selective. The measure is available to all companies on an equal footing. According to EEA (European Economic Area) state aid rules, a measure that is not selective does not constitute state aid," the agency said.

The EEA consists of European Union member countries in addition to EU outsiders Norway, Iceland and Liechtenstein.

(Reporting by Nerijus Adomaitis, editing by Terje Solsvik and Louise Heavens) ((nerijus.adomaitis@thomsonreuters.com; +47 9027 6699; Reuters Messaging: nerijus.adomaitis.thomsonreuters@reuters.net))