The IDF can use bunker buster bombs dropped in large clusters. Technology in satellites can penetrate the surface, identify the routes of the tunnels, and guide munitions targeted at them. Planning for that has probably been going on steadily for some time, with Israel watching their progress. When they have the right provocation from Hezbollah, the IDF will take care of the tunnels.
Yet, the only side that is worried about collateral damage is not the Islamic side.