ACC have introduced changes on plans and overdue amounts which did not previously apply.  This comes into effect from 1 April 2026.   

You can continue to pay your ACC invoice in full by the due date or you can choose to spread your levy payments over 3, 6 or 10 month instalment periods. 

For instalment plans, interest will now be charged on all new or roll-over levy instalment plans that were previously interest free; along with interest charges on overdue accounts.

The new instalment interest rates for the 2026 year (for new or roll-over instalment plans starting 1 April 2026) are 1.04% for the 3 month plan; 2.08% for the 6 month plan or 3.46% for the 10 month plan.  There will be an annualised interest rate which is made up of 2 parts - the first is a base rate (reviewed April each year) which for the 2026 year is 5.81%; and the second part will be a Use-of-Money adjustment which is fixed at 2.50% meaning an annualised interest rate of 8.31%.  This interest is calculated daily from the first day after the due date and compounded monthly.

For late payment of levies or instalments by the due date, late payment interest will apply at a rate of 1.69% for the 2026 year (starting 1 April 2026).  The rate is the annualised interest rate, converted to a monthly rate, plus 1%.  This interest is calculated daily after the due date and compounded monthly. 

For overpaid levies there will be credit interest.  If your provisional levies are $1,000.00 or more above your final levy, you may earn credit interest at a rate of 1.53% for the 2026 year (starting 1 April 2026).  This rate is set each year.