OH! I guess this isn't Kansas then, is it Toto.
So, if you are already under 1102 recommended cover, you must be pleanty close to the limit then, right. If you guys start using "heavy" farm equipment some day, that sounds like trouble. The reason API 1102 doesn't cover those shallow clearances is that 3 ft is the absolute minimum and 4 feet is the customary US depth for normal weight farm equipment passages, due to usual maximum depths of root plow penetration, and for unpaved track crossings. Yes, we bury the pipe at 4 feet cover in farmland. I and 1102 are telling you 750 mm isn't safe for what I/we would consider as "heavy farm equipment", no matter what is, or isn't, allowed under Oz standards.
Do Oz standards allow heavy farm equipment
passing on 750 mm cover, or is that really just the minimum clearance allowed, to which you must add extra depth when it is expected that "heavy" farm machinery will cross? Read your Oz code with a more critical eye and see if your opinion is still the same.
I'm afraid that with 750 mm cover, in a farm area where heavy equipment is active, I would want to fence off the RoW completely.
"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek