Opposition treasury spokesman Joe Hockey says Prime Minister Julia Gillard is feigning outrage over the behaviour of the banks.

Ms Gillard says it is unacceptable for ANZ to raise interest rates above the official increase.

She says the bank has behaved arrogantly and that people have a right to be angry.

But Mr Hockey says the Government still has not explained how it will rein in the banks.

"Julia Gillard is a timid person who confects anger but actually doesn't deliver on it," he said.

"These are just words from the Government, that's the thing. It's just empty words, empty rhetoric, raising expectations they're going to do something when they don't do anything."

From South Korea yesterday, Ms Gillard launched a broadside at what she called the "arrogant conduct" of two of Australia's big banks, after the ANZ's rate rise.

On Wednesday it raised its lending rate by 39 basis points, above the Reserve Bank's official increase of 25 basis points last week but below the Commonwealth Bank's 45-point increase.