What do these lights mean ?

[Dave_S]

Just went passed container ship docks, where they are reclaiming/extending the entry. The reclaimed section had a row of yellow flashing lights along its length but at the start i.e. before the reclaiming and still on the hard was a tower with a white 360° at the top, two greens one on top of the other and two reds horizontally in line with the greens.

It just looked like huge tricolour with an extra red and green.

[Lodesman]

Sounds like a dredging operation - the greens and reds indicate safe and obstructed sides, respectively.

[John_Trusty]

The yellow flashing were probably their dredging outflow pipe, and probably was not safe to navigate across. The dredge was covered under part of Rule 27 "Vessels Not Under Command or Restricted in Their Ability to Maneuver":
(d) A vessel engaged in dredging or underwater operations, when restricted in her ability to maneuver, shall exhibit the lights and shapes prescribed in subparagraphs (b)(i), (ii) and (iii) of this Rule and shall in addition, when an obstruction exists, exhibit:
(i) two all-round red lights or two balls in a vertical line to indicate the side on which the obstruction exists;
(ii) two all-round green lights or two diamonds in a vertical line to indicate the side on which another vessel may pass;
(iii) when at anchor, the lights or shapes prescribed in this paragraph instead of the lights or shape prescribed in Rule 30.

The flashing yellow on a pipeline is required in the US under inland rules, but I do not know if legally required in Oz:
§ 88.15 Lights on dredge pipelines
Dredge pipelines that are floating or supported on trestles shall display the following lights at night and in periods of restricted visibility.
(a) One row of yellow lights. The lights must be:
(1) Flashing 50 to 70 times per minute,
(2) Visible all around the horizon,
(3) Visible for at least 2 miles on a clear dark night,
(4) Not less than 1 and not more than 3.5 meters above the water,
(5) Approximately equally spaced, and
(6) Not more than 10 meters apart where the pipeline crosses a navigable channel. Where the pipeline does not cross a navigable channel the lights must be sufficient in number to clearly show the pipeline’s length and course.
(b) Two red lights at each end of the pipeline, including the ends in a channel where the pipeline is separated to allow vessels to pass (whether open or closed). The lights must be:
(1) Visible all around the horizon, and
(2) Visible for at least 2 miles on a clear dark night, and
(3) One meter apart in a vertical line with the lower light at the same
height above the water as the flashing yellow light.