National Insurance (NI) or Social Security system has been developed in many countries to provide certain benefits to the people in those countries. These are initially contributory systems of insurance against risks, like illness, unemployment or disability and later also provide retirement pensions and other benefits. Contribution rates vary from country to country and both employee and the employer jointly pay the total contributions. All residents with residence permit in Norway for instance, are mainly members of the National Insurance Scheme in Norway (Folketrygd). Likewise, for an employee being sent to work abroad, the country of employment may require the assignee to pay the contributions in that country. Without some means of coordinating Social Security coverage, people who work outside Norway may find themselves covered under the systems of two countries simultaneously for the same work.

Social security agreements between countries eliminate such dual Social Security coverage and contributions while maintaining the coverage under the system of the country where they are likely to have the greatest attachment. Norway has social security agreements with several countries. The most comprehensive agreement is with the EEA-countries (EØS avtale). In addition, Norway has bilateral agreement with Australia, Canada (separate agreement with Quebec), Chile, Switzerland, and Turkey.