A limit and a balance are different
The amount already borrowed is not the same as the total credit available on a card. KLP explains that unused credit limits can affect the amount a bank is willing to lend for a home. Its article is general background, not a personalised mortgage decision or a current offer.
Check the information recorded
Gjeldsregisteret covers unsecured consumer credit, including credit cards. It does not provide a complete picture of all your debts: mortgage, car and student loans are outside the scope described in its FAQ. Check your information through its official access service, and ask the reporting lender to correct any errors.
Discuss unused limits with the bank
Ask your mortgage bank how existing limits are treated in your situation. If you choose to reduce or close a limit, arrange it with the card issuer and check the subsequent record. Paying the balance does not automatically close the credit facility. No particular increase in borrowing capacity or mortgage approval is promised here.