SA departments to face late payment fines

South Australian government departments will face penalties if they fail to pay their bills on time.

As part of the new Liberal government's pre-election commitment to improve transparency and accountability, late payments will be reported to ministers with the information then made public.

Departments will also have to cover the cost of any penalties paid to suppliers from their existing budgets, Treasurer Rob Lucas says.

The penalties will be equal to five per cent of the outstanding bill plus an added amount to cover interest, currently an additional 1.5 per cent.

Mr Lucas said the government didn't want government departments to be hit with the extra costs and to avoid them all they needed to do was to pay their bills on time.

"The bottom line is it's a relatively simple matter to pay your bills on time," the treasurer said.