Hundreds of Commonwealth Bank of Australia (CBA) customers have reported receiving emails designed to skim money from their accounts, forcing several of them to change their passwords as a precaution.

The bank issued an official alert over a fresh batch of email 'phishing' frauds that used authentic-looking logos and seeking customers' personal details.

The frauds cover requests for people to participate in surveys, update account details, activate cards, win prizes and money, qualify for fee refunds and unlock frozen accounts.

According to retail banking service group executive Ross McEwan six hoaxes had been tracked circulating in Australia and overseas. He added that the emails appear authentic and include Commonwealth Bank logos. The refer to actual bank staff members or include believable email addresses he warned.

He said that while many people deleted the emails, some might end up as unsuspecting victims. He added that the bank did not use email to seek personal information from customers.

He asked consumers to upgrade spam filters on computers where possible.

Meanwhile, the bank has completed a $50-million overhaul of its online portal that would give access to all its products through a single site.

The revamped NetBank portal brought together some previously frozen services such as CommSec, CommBiz and CommInsure and migrates processes such as opening accounts and accepting contracts, online.

With the revamped portal Comonwealth's 2.6 million NetBank users would be able to eliminate multiple sessions, according to chief information officer, Michael Harte.

Customers will be able to access all online products using only one password.

The new-look application handling about $20 billion worth of transactions every month would allow customers to reposition regularly used content in more prominent positions on the site and to initiate web-chat sessions with service staff.

Harte said that the bank would now increasingly render SAP through Finest Online which would allow customers to be increasingly migrated from bathc processes for the services that needed to occur in real time.

Previously it would take weeks to make changes in customer home loans, but the process could now be done in a matter of minutes he said.

Harte declined to give a figure about the cost of the service but said that 'front-end' costs amounted to $50 million.

The project completion comes as major Australian banks continue to squeeze budgets in response to the ongoing global financial crisis. CBA too has been impacted by the crisis. Last year it moved to reduce costs by 5 per cent by cutting costs at least $370 million from its bottom line through technology and staff cuts and shelving IT projects.