Last Friday, ANZ lifted its variable mortgage rate by 0.06 per cent, citing funding cost pressures.

In response, Treasurer Wayne Swan predicted the bank's decision would see customers ''asking whether ANZ deserves their loyalty and looking closely at the better deals on offer from other financial institutions''.

He said a lot of customers would be very upset by the rate hike, ''coming after their recent massive profit announcement and staff sackings''.

But this morning, Mr Robb - who is acting shadow treasurer while Joe Hockey is in London - blamed the government for putting pressure on interest rates, which has increased the cost of money.

''I don't think [ANZ] would willy-nilly put up their margin like this if they weren't, if they weren't suffering a problem with their margins,'' he said.

When asked about ANZ's huge profits, Mr Robb said that Australians depended on banks performing because of their links with superannuation funds.

''It's the return on capital and things,'' he said.

''Do you want them to have a loss before they can put up their margins?''

This morning Mr Swan said that families and and businesses would be ''rightly ropeable'' with Mr Robb ''out there this morning defending ANZ for jacking up its rates last Friday''.

''Andrew Robb is out there going into bat for a huge bank over struggling families,'' Mr Swan said in a statement.

This morning, Opposition Leader Tony Abbott would not specifically defend the ANZ and its decision to raise rates. But he joined Mr Robb in criticising the government's economic management.

"Look, I'm not here to defend the banks, the banks are quite capable of defending themselves," he told reporters in Melbourne.

Mr Abbott said the banks operated in an economic environment that had been "contaminated" by the government's policies.

"The problem is we've got a government which doesn't understand basic economics," Mr Abbott said.

This afternoon, Employment Minister Bill Shorten said that Mr Abbott had rebuked Mr Robb by failing to back his comments on ANZ.

"I note that Tony Abbott's playing the game 'man overboard' with Andrew Robb," Mr Shorten told reporters in Canberra.

''He clearly thinks Andrew Robb has gone too far in defending the banks."

Last month, Mr Robb was accused of speaking off-script, when he contradicted Mr Abbott's commitment to his flagship paid parental leave policy.

In February, Mr Robb also appeared to be at odds with Coalition colleagues when he would not commit the Opposition to a budget surplus if they won government.

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