I will be interested in how you go as I will be there in the middle of January 

 Cod are very few and far between in the weir same for trout. Plenty of redfin, carp and yellowbelly though. If you've got a car, it's worth driving up the river arm towards talmalmo where the fairy crosses, more chance of cod up that way.

 cod are a mythical thing, but as you've already sait, plenty of reddies around. 

There are cod in the weir, but few and far between, I lived at Bellbridge right on the weir some years back, caught plenty of trout and redfin, but never saw a cod pulled out. As lebo mentioned, up steam to Talmalmo or Jingellic you have a better chance, but they can be hard to find without a bit of local knowledge. Live yabbies hooked through the tail will get them, but the yabbies love to drag themselves into snags so can be frustrating. My go to lures for trout were Helin Flatfish in frog pattern for trolling, or Wigston Tassie Devils for either trolling or casting. There are also areas downstream from the weir that hold both trout and cod, but there is/was an exclusion zone where you can't fish, so make sure you are outside the zone, they will book you. Also be sure to have a NSW licence regardless of which side of the river you are fishing from, the Murray is deemed NSW waters.
Good luck !

 And put the cod to ground.  We are in Rutherglen at the moment and had hoped to fish the Ovens which has plenty of cod but it is over its banks after 213mm of rain in the catchment in three days. The wineries make up for the absence of fish but did actually catch a silver perch .....another ticked off the list.

 Hey sunshine, I heard that silver perch are now a protected species and must be returned. Any idea if this correct or just a rumour ?

Was only a small fish but still put a big smile on my dial.  Fed the carp to the Pelicans, didn't matter how large the pellies wolfed em down. Good riddance to the bloody things, they are presently debating introducing a virus which will wipe them out but issues remain as to what you do with billions of rotting carp carcasses which would litter the banks for thousands of kilometres.  Oddly there are less and less carp the higher up the Murray we travel. Heaps at Mannum, less at Echuca and even less where we are now......perhaps the cod are managing to keep in check?  

 Yeah apparently cod are plenty in the rivers but I have found large scales on the banks of the lake, but most locals have said they are scarce there. Sussed a few other cool spots further up and I'm going to try the ferry crossing soon. 

There wasnt that much rain like they thought but still was pretty damp. Newspaper headlines read storm fails to  perform, where I am was sposed to be underwater but it stayed pretty tame. Sounds like the Ovens would be good after it settles a bit, keep us posted and vice versa and good luck.

 There's no shortage of carp all the way up the river to groggin now. They've changed their feeding habits over the years from mainly bottom feeding in slow shallow back waters to surface feeding and in fast current waters. This virus sounds promising! Not sure what they'll do with a million tonnes of dead carp though.

 No carp at all in evidence but cod a plenty !

After a long two weeks working 11hr days, I'm redfin master. No cod for us but we saw alot of large carp at the dam wall and I'm gonna have a final crack tonight before be depart. All in all a good experience, got some sweet lures and learnt a few things. Cheers for the help people !