The money is owed by One.Tel, the failed Murdoch-Packer backed Australian telecommunications company.
Although Optus will try to recover the money from One.Tel, it has made the decision to write the money off against profit for first half results. One.Tel administrators have indicated that creditors cannot be certain of recovering any money.
The write-off will be booked as a one-off item against first-half results in September.
One.Tel went into voluntary liquidation last month with debts of more than A$600million.
