I think a dove grey 3 piece would be a nice nod to tradition - morning coat and vest - without looking like a costume and being useful later as business or other wear . The vest would make the groom stand out and let the grooms persons wear two piece suits and the grey provide a good neutral enough palate for the bride and brides maids etc. Whip off the vest after the speeches and formal bits.
Or you could go all iGentt AAAC and get a morning coat and get up and then change into a Dinner Jacket and pants for evening. This only works if you are in certain circles in Australia and if you are in those circles you wouldn't be asking anyway.