Oh there are, rules around employees, consumer guarantees act, acc levies and various other things. But it seems unlikely that have just 2 food suppliers isn’t a root cause of food price issues.

Australian here

Isn't it mostly just economies of scale plus transport costs?

Or are our industrial relations laws really not as good?

It's more about farming subsidies and tax levels. Some governments choose to make food cheap by encouraging overproduction.

Overproduction (by subsidy) is also very useful to cope with poor harvests, supply shortages due to wars etc.

Discussion on the European system for this: https://en.wikipedia.org/wiki/Common_Agricultural_Policy#Ove...