She organised an art auction last year, and raised $15,000 to fund Kiwis Against Seabed Mining (KASM) in its fight against the mining application.
"I was thinking that was where it was going to end. Now with this going through I just felt like I have to do something."
Light rain is expected on Sunday. As well as the human chain, children will be able to make hearts with pebbles pressed into the sand, then gather them up and throw them symbolically into the sea.
There will be a collection bucket, with half the proceeds going to KASM and half to South Taranaki tribe Ngāti Ruanui. Both plan to appeal the mining decision.
The protest will be filmed by Hawera's Kiwa design and website management business. It can then be put online.
For more information, see the Save our Sea Facebook page.