Hundreds defied the weather for the opening of a riverside walkway in central Christchurch. (Video first published in December 2018)

Christchurch's new river promenade needs to be more popular with people than ducks, city agencies says.

Seats on the promenade between Colombo and Manchester St have been encrusted with duck poo since the $120 million Avon River precinct opened last week.

Christchurch City Council's acting head of parks Grant MacLeod said that section of the promenade was cleaned with water blasters one to three times a week.

"We'll have to continue monitoring the area as we may need to increase our reactive cleaning," MacLeod said.

AMANDA CROPP/STUFF Christchurch's new promenade has been popular with ducks. "The more people use the space, the less the ducks will," city agencies say.

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However, he said the promenade was like the Terraces: "The more people use the space, the less the ducks will."

A spokesman for Crown rebuild agency Ōtākaro had a similar response.

"The more that people use a space the less interest there will be from the birds so the need for cleaning decreases over time."

AMANDA CROPP/STUFF Seats along the promenade between Colombo and Manchester St.

Asked to clarify this reasoning, the spokesman said that "the more space people take up the less space ducks can take up".

Hundreds of people attended the opening of the 2 kilometre-long path, which runs alongside Oxford Tce from the hospital to the Margaret Mahy playground, on November 25.

The Avon River precinct was the first of the city's anchor rebuild projects to get under way, with work starting near the Antigua boatsheds in 2013. It was originally hoped it would be finished by late 2014.