If you pay wages or other remuneration for someone's work, you must pay employer's National Insurance contributions unless the person in question is self-employed. Be particularly aware of remuneration in the form of commissions, overtime pay, inconvenience supplements, tips and similar.
You must deduct and pay tax for all remuneration to employees that you pay employer's National Insurance contributions for. An important addition to this is that you must pay employer's National Insurance contributions for pension contributions and holiday pay. The basis for employer's National Insurance contributions and tax withholdings also includes union dues and maintenance payments (even if they have been deducted from the amount paid to the wage earner).
The Norwegian Tax Administrations prepares a List of Codes for Certificates of Pay and Tax Deducted each year. In this list, all types of income and other payments are assigned separate code numbers. If a numerical code is followed by the letter 'A' (for example 111-A, 112-A etc.), this means that the payment is to be included in the basis for calculation of employer's National Insurance contributions.