Can anyone recommend a broker for trading bonds listed on NZDX / ASX?

I have an account with OMF but they don't offer this service. Shame because they seem to be pretty good in other areas.

Next I approached ASB Securities who were very unhelpful, although I'm not suprised as my mortgage is with them and their customer service is poor.

I had a look at BNZ but their fees are rather high.

Not sure where to go next - what options do I have? I was told that after the GFC 2007/8 it's only really the big banks that offer this service, not sure how true it is (was a broker who told me).