A milestone in the cleanup of Christchurch's Avon River.

After more than a year of cleaning and rehabilitation, the in-river works are complete.

Almost 10,000 tonnes of liquefaction sand and silt has been removed.

Crews also cleaned 15,000 square metres of gravel beds, rescued more than 1500 fish and planted nearly 10,000 plants along the river.

Associate Canterbury Earthquake Recovery Minister Nicky Wagner says already fish are flourishing, water is flowing faster and the riverbed is cleaner.