ANZ says its app and internet banking services are coming back online after a major outage prevented some customers from accessing the services.

The outage was first reported around midday on Tuesday.

A few hours later ANZ said the impacted systems were coming back online.

"Access to the ANZ App, Internet Banking and ANZ Transactive Global began to come back online from 2:45pm AEST," an ANZ spokesperson said in a statement.

"We continue our work to resolve any outstanding impacts as soon as possible and apologise for the inconvenience," the spokesperson said.

In a statement shared on X, the bank said it was investigating a technology issue relating to a third party vendor.

ANZ said its ATMs, phone banking, the ANZ Plus app and EFTPOS facilities remained available during the outage.

Its rival Commonwealth Bank suffered a similar major outage in March that prevented customers from accessing online services.

AAP/ABC