you won't like this:
(for your debit card)
In addition, when you use your debit card at an overseas ATM you
will pay an $8 international transaction fee on your
transaction.
However, If you use your Westpac card at any bank that belongs to
the ATM Global Alliance, you won't be charged the usual $8
international transaction fee. Banks in the alliance are located in
Australia, North America, UK, Europe, and Africa. Find out which
banks are in the ATM Global Alliance...
(for withdrawing money)
When withdrawing cash from your savings or transaction accounts,
you can save a fee of $5 by using the ATMs of participating Global
Alliance partners in the following countries:
but it doesn't say Singapore in the "following countries", so it's
A$5 per transaction
clicky here =>
Westpac stuff