I did that exact same connection last year. Had no major problems, though both my flights were on the same PNR (last 2 sectors of a DAS13). Had to get the QF10 boarding pass at SIN transit desk as they didn't issue it at my starting point (ICN) and wouldn't issue it at HKG. Had time for some food and a shower up at the QF lounges. CX735 also had to do a TOGA. Had a rain storm and wind shear at the end of the runway about 10 seconds from touching down.
QF10 departed SIN after 2100 after boarding on time. Captain said it was due to having to arrive over MEL after 6am as the runway at MEL the A380 needed didn't open until 6.

I've made a 30 minute connection (JL-QF) at SIN before without issue (including having to go via the transit counter).