I think, without any checked baggage, you have a 95% chance of making this connection: in the last sixty days, MH 149 has only been more than forty-five minutes late four times. However, the longest delay in that period was over four hours.
If you do have checked in luggage (and I've just noticed that in the question, sorry) I think you should forget this plan or forget the luggage.
MH might not check your luggage through to CI–in which case you would also have passports, bag collection, customs, bag drop, and passports again. However, MH and CI have signed a baggage interline agreement so in principle a competent check in agent could accomplish this, but that's up to company policy.
On the flip side, CI 57 only runs thrice weekly, and I think, even if they were sympathetic about your position, it's unlikely they would endorse your ticket onto another carrier: so if you miss your flight, are you happy to buy a new walk up ticket? Or wait around in Melbourne until another seat can be made available to you? Also, if you have onward flights on that ticket, they would be cancelled as well.
If you are not happy to pay for new flights, you should not take the risk.
Sometimes I accept that it is necessary to take this kind of a risk if your scheduling is very tight and hopefully someone else is paying the bill. However I would be reluctant to take this risk unless I really could not find a better way of arranging it.