Three of the four major banks have lowered their term deposit rates, just a week after the Reserve Bank raised official interest rates.

ANZ Bank, Westpac and National Australia Bank have all lowered rates on term deposits, some by as much 50 basis points, or half a percentage point, according to data from Canstar Cannex.

Since Thursday, ANZ Bank has lowered the interest rate on a four-month term deposit of between $5000 to $99,999 by 40 basis points to 5.1 per cent.

National Australia Bank's four-month deposit on between $5000 and $9999 fell by 50 basis points to 6.3 per cent, Canstar said. Some other NAB rates also fell.

At the same time, Westpac's four-month rate on a deposit between $5000 to $9999 fell by 10 basis points to 5 per cent.

Commonwealth Bank had not announced any changes to its term deposit rates. Calls to the bank were not immediately answered.

Term deposit rates, important to savers who choose whether to roll over their nest eggs with the same bank, or shop around for better returns, move not only because of interest rate expectations, Canstar Cannex financial analyst Peter Arnold said.

They also move because of funding changes - how much banks pay for cash borrowed - over certain terms and changes in banks' need for funding over certain terms.

"The lowering in term deposit rates across the board is more likely due to external factors such as changes in money market rates that have affected either their cost of funding, or their need for funding from the deposit book."

Not all term deposit rates have fallen. The ANZ bank added 50 basis points to a three-year rate for deposits of between $5000 and $24,999 to 6.88 per cent.

"These change weekly depending on market conditions and our funding strategy," said a spokeswoman for the ANZ.

The overall trend, however, was for lower term deposit rates at NAB and Westpac, the data showed.

Mr Arnold said if banks reduced the variable deposit rates for ongoing savings rates, there would be more cause for concern from consumers.

The major banks passed on the RBA's 25-basis-point rate rise this month on regular savings accounts, data shows.

Banks have begun to more aggressively court deposits on regular accounts in an effort to win more retail customers, thereby increasing market share.

Australia's banks are also anxious to source more fund onshore rather than depend on the pricier and more fickle international wholesale funds market.

czappone@fairfax.com.au

BusinessDay