THIS time last year, the Coffs Harbour International Marina was devastated by an east coast low.

Yachts were destroyed and rocks from the Northern Breakwater were tossed over the marina-side by monstrous waves, which hit on June 4 and 5 last year.

But today, given the impressive rebuild of public and private assets, you would be excused if you missed the few clues that offer a glimpse of the storm's destruction.

Coffs Harbour International Marina manager Elise Currey, walking on the refurbished boardwalk, said the legs of the mooring fingers were last year sticking in the air following the storm.

Ms Currey said the storm was made up of a cocktail of "king tides, big seas and northern winds".

"You always underestimate it, you don't think it can get that big," she said.

"It was very noisy and scary."

Ms Currey said the marina had weathered through east coast lows in 2009, 2012 and 2015 but the low last year was one of the biggest.

"It's a little like being in a snow globe and someone's shaken it up," she said.

Ms Currey said the marina office was left in tatters after a large rock dislodged and broke through the back of the structure.

But fast forward 12 months and you would never guess such a destructive storm had hit.

Ms Currey said repair work finished in March and the marina was back to running the same as before the storm.

She said the marina was stronger and upgrades to the Northern Breakwater - making it wider and adding a submerged berm - should minimise damage caused by future storms.

"It's got a berm, so that takes the energy of the waves," she said.

NSW Department of Industry - Lands indicated the berm would contain 30,000 tonnes of rock.

In addition to the berm, 12-tonne concrete blocks known as hanbars will be placed along the breakwater and raise it about 0.75m.

The Northern Breakwater was built in 1924. On average, waves overtop the breakwater several times a year.