When your super reaches a balance of $1.7m you can only contribute the concessional amount each year which is currently $27500. I believe they introduced the cap to stop the non concessional contributions which is currently $110,000 per year. And you can bring forward 3 years of $330k every 3 years.
The only loophole I can see is that you could contribute that $330k on the 1st of July if your balance was at $1.69m as of the 30 June.
So the 10s of millions will have to be made from a base of approximately $1.7m - $2m.