The Commonwealth Bank's Web site and ATM went offline for five hours Wednesday, angering customers who could not withdraw money and perform other online transactions.

The bank restored the service by 11 p.m. and apologised for the inconvenience.

Online services were disconnected starting 5:30 p.m., and EFTPOS purchases and phone banking were also affected.

Commonwealth Bank spokesman Steve Batten cited network connectivity problems as the cause of the service disruption.

The bank's contact centres were flooded with calls, making it unaccessible too.

Employers failed to send paychecks to the accounts of staff and advised that it will be delayed. Batten said those who have yet to get their paychecks will see them coming through as the day progressed, according to News.com.au.

Other customers complained through social networking sites that their accounts are showing incorrect balances.

Batten advised that those who have money missing from their accounts should contact the bank to resolve the issue.

Other complaints were ATM cards stuck inside machines and inabillity to buy Christmas gifts.

It was the not the first time that Commonwealth Bank's server crashed. Exactly one year ago, the same disruption happened.