seasnakeblanche's Identifications

This snake looked dead until I touched it and it moved. The close-up shows an "alive eye".
NSW National Parks has a brochure noting that 11 sea snakes have been observed in NSW but only rarely and as vagrants, the exception being the Yellow-bellied Sea Snake (Pelamis platurus). That one has a different head shape to this record and the head scale pattern does not quite match. So I checked all 10 species on iNatAU and there are few or no records for NSW - Stokes Sea Snake has a record (Coffs Harbour), 4 records for the Bar bellied Sea Snake and 2 for the Olive headed sea snake.
The photos look closest to the Olive Sea Snake (Aipysurus laevis) but the head scale pattern is not quite the same.