Yeah, oddly enough it does not advise you on the application form.When I applied for a NAB card earlier this year, I found that the NAB system expects your FF number to be 10 digits. So if yours is not, you need to add the appropriate number of zeros in front of it to get to 10. That is what the person I spoke to on the phone said anyway when I called up to add it.
When I rang up a second time to check (the first time was done in a branch), the person started with some leading zeros upon verification.
Wondering why they would expect reasonable people to know that.