(1) Where any amount, including an estimate under the provisions of article 20D, which a contributor is liable to pay in respect of a self-employment contribution is not so paid, simple interest on the amount may be paid by the self-employed contributor and such interest shall be calculated at the rate at which, for the time being, interest is chargeable on unpaid income tax under section 991 of the Taxes Consolidation Act, 1997 (No. 39 of 1997) and from the expiration of the time specified in article 20B.

(2) Interest charged on self-employment contributions in respect of which article 20A applies, shall be collected and recoverable by the Minister and paid into the Social Insurance Fund.