More major lenders moved rates over the weekend, but ANZ is still the only bank to pass on the rates in full.
NAB has so far kept its promise to be the lowest of the big four and passed on 21 of the 25 basis points cut by the Reserve Bank.
The bank announced that it was cutting its standard variable home loan rate from 6.99 per cent to 6.78 per cent late last week.
NAB calculates the cut will save customers on average $52.50 per month.
Westpac also cut rates, but also refused to pass on the full 25 basis points.
The headline standard variable mortgage was cut by 20 basis points down to 6.89 per cent.
Westpac also announced a new three year fixed rate home loan offer with 5.89 per cent with discount.
Since October 2011, Westpac has cut its variable mortgage rates by 0.97 percentage points, equating to an annual saving of $2,388 on an average home loan.
Westpac Group Executive Retail and Business Banking's Jason Yetton said the balance was hard to maintain.
“This has been a difficult decision as we have sought to balance the needs of our mortgage customers with those of our millions of savers, particularly retirees who depend on the income from their deposit accounts.”
Westpac did however pass on the full 25 basis points to small business loans.
“Despite increased funding costs, we recognise that it is particularly important at this time to help small business in this way given the critical part this sector plays in supporting the economy and maintaining employment as a whole.”
CBA also reduced its SVR by 21 basis points, to commence on June 18.