Dear Madam,
Although I am not aware of any legal principle which would give you a determination wither way, I think you would be justified in refusing to pay interest. There are general obligations on employers to ensure that payments to employees are recorded and administered accurately and the employer does have to take some responsiblity for ensuring their payment system is administered accurately. ALthough on this topic appears to be quite vague and I cannot find a spefic instance of this occuring, from the point of view of natural justice, you shouldnt have to accept a charge of interest in this case, I believe.
Regrads,
XXXXX XXXXXXX
Lawyer
BEc(SocSci). LLB (Usyd) - 5 years of Work Experience