Australian communications provider Telstra apologized Friday for a massive leak of customer details occurred online.

Local newspaper Fairfax on Wednesday found that a Google search could easily get to Telstra spreadsheets, obtaining customer names, telephone numbers, and even business and home addresses.

More than 1,600 customer records were leaked in one of the spreadsheets, which contained Telstra customers' personal details. A further three spreadsheets contained over 8,200 customer records, according to Fairfax.

Telstra removed access to the data soon after being notified by Fairfax. The company issued a formal apology to affected customers on Friday, saying an investigation is underway.

Peter Jamieson, Telstra executive director of customer service, said the breach was "concerning" and "unacceptable," vowing to take all steps to ensure they protect further information.

Australian IT security researchers warned that the customer data may potentially be used by someone with malicious intent to obtain more customer information by pretending as a Telstra call center representative.

Telstra hasn't been doing well for keeping customer information private and has caused a number of customer data breaches in recent years.

One of the most serious bug happened in 2012, in which the details of almost 800,000 customers was found to be exposed online without password protection.