Japanese tunnels between Deepwater & Repulse Bays [????- ]

Craig spotted this one on the 1945 photo shown below:

If you zoom toward the lefthand side of the photo, to where to roads bend out of sight towards deepwater bay, you should be able to see 3 massive Japanese Tunnel entrances.

I always suspected they were there as you can make out a very square looking bricked up section, but it has mostly been sprayed with concrete so its difficult to notice now.  You can also see where they tipped all of the dug out rocks and earth down the side of the hill.

They have been completely sealed up now and hardly noticeable now that they have recently sprayed concrete over the area. I noticed them a number of years ago when they were more obvious and bricked up. Due to the size, shape and location: I suspect that they held Anti-Shipping Artillery (at least 75mm).

I even seem to recall a rumor (I can't remember from who though) that they had Japanese Tankettes.... but I really don't know how accurate that is, but if the Japanese did have any number of smaller tanks on the Island then that would be a decent place to keep between Repulse bay and Deepwater bay in case of any Allied landing there, so it is plausible I suppose.