The new Harakeke Waterway between Maraenui and Marewa has been reshaped and transformed into a more natural waterway with pathways and recreation areas.
About 100 people from the local community turned up to help plant 2800 plants on Saturday.
A large number of keen school children who had already planted with their schools during the week joined them.
"It is a great response from the volunteers who turned up," said the regional council's environmental engineer Patrick Whitesell. "They can be proud of their hard work which has contributed a huge amount to the transformation of this area, and we couldn't have done it so efficiently without them." The planting day had been postponed due to bad weather in June and July, which held up the earthworks.
The space will be developed further for local neighbourhoods to enjoy.
Napier City Council are expected to install bridges, a paved pathway and plant more trees by the end of the year.