Emergency response workers from Natural Resources Wales have started preparatory work to repair flood defences in Llanbedr, near Harlech.
The flood embankments were damaged during the recent storms causing a 50 metre breach in the defence.
As a result five homes and more than a thousand acres of agricultural land have been flooded twice each day from the incoming tide.
Natural Resources Wales has been investigating the best way to repair the sea defence to stop the flooding so the homes and farmland can recover.
In order to repair the flood embankments, workers will be creating a temporary 1km road so they can move the 15,000 tonnes of boulders, clay and soil needed to fill the breach.
The work will be more difficult because work will have to stop at every high tide as the site will be flooded. Careful planning is also needed to avoid damaging internationally important wildlife habitats nearby.
The flood defence is an important asset not only protecting the homes and farm land, but also the tourist hot-spot of Shell Island, an airfield earmarked for development and transport links in the area.
Tim Jones, from Natural Resources Wales said: “We sympathise wholeheartedly with the people who have been affected by this breach. It has been a terrible start to the year for them.
“The need for detailed planning on this scheme means that it has taken a little longer to start work than we would have liked. But while we were doing that we have also carried out many urgent repairs on sea defences in other parts of Wales. “Although the storm caused devastation along the Welsh coast, tens of thousands of homes were protected.”