Castlecliff Coast Care's Graham Pearson was collecting seeds from the spinifex and pīngao plants in the sand dunes at Castlecliff Beach this week.
The native sand-binding sedge plants are a vital part of the beach ecosystem, Pearson said.
"Not only do they help keep the dunes in place but they form a barrier to prevent blow-outs so the more we have, the better.
"We have around 2000 plants that we will use for the new dune that has been formed at Morgan St but it needs a lot more - around 10,000 will be required to make it really stable."
Pearson sends the harvested seeds to a specialist coastal plant grower in Whakatāne and when the seedlings are well-established they are sent back to Whanganui for planting.
Coast Lands nursery has specially built facilities that allow them to propagate, grow and supply coastal natives for large environmental projects, coast care groups, councils and private landowners throughout New Zealand and Pearson said the cost works out at around $2 per seedling.
"The seeds that I'm sending now will be ready for planting in July next year so it takes around 17 months until they are established enough to survive in the dunes."
Pearson and his wife Lynn established the Castlecliff Coast Care restoration project 13 years ago with the aim of stabilising and enhancing the biodiversity of the dunes while encouraging the community via participation and education.
The project receives regular support from Aranui School, Whanganui High School, Whanganui City College, Idea Services and a number of other adult volunteers.
"Idea Services were meant to come down this week but had to cancel due to Covid restrictions," Pearson said.
"They will be disappointed because they always enjoy it."
He hopes the current Covid-19 restrictions will be lifted this weekend as Whanganui is looking forward to hosting the Coastal Restoration Trust of New Zealand– Tahuna Ora national conference next week.
The theme of the conference is Living on a Dynamic Coast - Ko Te Kawa o Tangaroa, he kawa ora.
"There are some fantastic speakers lined up and there are a lot of people coming," Pearson said.
"The main part of the conference will be held at The Grand from Wednesday and that part of the conference was booked out well in advance."
A free coastal restoration workshop to be held at the Duncan Pavilion on Tuesday is also booked out.
A few spaces are still available for a number of field trips and other activities planned for the conference, which runs from Wednesday to Friday. Those who have missed out on the main events are advised to add their names to a waiting list in case of cancellations.
Visit coastalrestorationtrust.org.nz to register interest or find out more.
The conference is sponsored by Horizons Regional Council, Whanganui District Council, Progress Castlecliff, Whanganui River Traders Market, Downer, Coast Lands, Totara Glen Nurseries and Daltons.