Water wings is totally correct. All this would really do is make a currently unsafe airport safer for existing operations. In practical terms it won't provide much additional useable runway length.
Furthermore, even if additional runway was provided who exactly is going to use it? Long haul ops out of WLG are a pipe dream. CBR and WLG are similar sizes, but CBR is a couple of hours flying time close to most markets. If CBR can't justify longhaul ops I can't see how WLG could. ( Don't be fooled by the fact that CHC has some longhaul ops, it is the inbound gateway for longhaul tourists to the South Island - WLG would be an inbound gateway to what exactly? ... WLG and the Wairarapa vineyards? )