Australia’s four big banks have ripped-off $1B by keeping the majority of the Reserve Bank's last rate cut to themselves.

Figures obtained by The Daily Telegraph show households were robbed of just over $800M in repayment savings - on an annualised basis - as the banks failed to match the RBA's rate cut of 0.25 per cent.

The biggest benefactor was NAB which held on to $240M by keeping its standard variable rate on hold.

The Commonwealth, which boasts about $160B of variable home loans on its books, gouged $239M by lowering its rate by 0.1 per cent.

The ANZ Bank & Westpac both lowered their variable rates by the same margin yesterday & stand to pocket $152M & $171M respectively.

The figures also show the banks could easily expect to save more than $100M by keeping their business variable rates on hold - which all did bar Westpac.

The move to withhold most of the savings from home owners angered Wayne Swan, who, with Kevin Rudd, urged the major banks to review their decisions, The Australian reports.

"The failure of the banks to pass on this rate cut does blunt the effectiveness of monetary policy & of course, does leave many customers with a higher burden than they otherwise should have," Mr Swan said.

"I'm pretty disappointed with what they've done. They take their commercial decisions. They'll have to justify their position in the court of public opinion. They do need a good kick up the bum occasionally. So, on this occasion, I'm not happy with it. The Prime Minister isn't happy with it. He's asked them to reconsider."

The banks' decisions came as figures showed they have blanket coverage of the local housing market. More than 90 per cent of mortgages in Australia are held by the banks, with the institutions growing their share as the non-bank lenders exit the market.