The Port Line ship is likely to be Port Alfred.

The reason the "ENNA G" is tied up at the old Clyde Quay wharf is because she was the subject of a dispute between her owners ( Nauru Local Government Council) and the New Zealand Govt. Her Fijian crew had been summarily dismissed and she had been due to enter the Wellington Floating Dock in May 1973. This dispute was settled in September 1973; there were never ending troubles over getting paid for services provided to the Nauru Line.
Some more information here:
http://ssmaritime.com/MV-Prinses-Margriet-Enna-G.htm

The ship in the background is the laid up 'Maori'
http://www.nzmaritime.co.nz/maori3.htm
The ship in the foreground could be any of a number of Port Liners built in the 50's.

Wonderful bit of knowledge Cisco, Cheers,Graeme.

Interesting... a Nauru ship that at first glance at the thumbnail I thought was going to be Port line...
Ship on the left is Enna G... ex Prinses Margriet
http://www.shipspotting.com/gallery/photo.php?lid=1339029