I have got to agree with KPC and say that it is possibly the Waimea. She was a regular runner into Lyttleton around the time this photo would have been taken. Possibly on the steel run Sydney, Newcastle, Port Kembla.
Used to lay at #3 Wharf. I did three trips on Wiamea including bringing a circus from Sydney to Lyttelton...think it was Sole Bros...Deck cargo of assorted beasts...with the usual load of steel below. Wiamea was a real work horse on the Sth Island steel run...mainly dunedin crowd. Hard yakka and a mongrel to clew up..they were the days
I also sailed on the Waimea as Deck Boy, Ordinary Seaman, A.B. and Bosun.
As stated she was a work. horse She normaly was a hard one to clew up as she at times had a lot of deck cargo . No 3 gear was a problem as it was ratchet gear and I have seen a derrick come down rather quickly. She did have a regular core of South Islanders on her who had been in her for years one in particular cannot remember his christian name but surname was Harris.He was out of Dunedin. The Masters if my memory serves me right were Captains Pugh Williams. Brayshay, and Rideout,cannot remember 4th one. I had a soft spot for her as she always seemed to be a happy one to sail on.She was on the Melbourne South Island Run for a long time until replaced by Waikare another great job. The Waimea then went out of Wellington for a while and then ventured North out of Tauranga with Paper.
She also seemed to carry a lot of livestock in the tween deck aft plus the horse stalls. She was in the Company from 1953 To 1975.
I have attached three additional photo's taken day which may assist you in identifing the ship. There was a blue star ship in port as well as two other ussc ships and a local coaster which has the accomodation aft. Maybe you can ID all ships in port that day. We were at the tanker wharf astern of the Danish tanker Tuborg. Would the Lyytleton Harbour Board still have records of which ships that were in port about that time. Trouble is I cannot remember what day it was, altough the month was around July 1966 or 67. My old notes say that some of the crew on the ship I was on were going to walk off over time off and leave etc. Not to sure what the outcome was but we did sail for New Plymonth and into a storm on entering Cook Strait.