If you believe the world economy is heading for trouble that...

If you believe the world economy is heading for trouble that would force the RBA to cut rates. So buying Australian bonds will give you unbeatable returns.

And having further to cut rates simply means we have further to fall (as the RBA chases the market down over coming months & years).

If you don't believe this scenario, the only other government guaranteed investment is bank deposits returning the highest yield of any G20 bank with the lowest risk (given our low level of public debt). Either way, both are safe options to ride out the growing global macro risks which are becoming increasingly deflationary.