"I've only got two or three pieces left," said Mr de la Haye.
He had also picked up commissions from the hundreds of people who streamed through their property.
"We had over 260 last weekend and over 130 yesterday, and today's tracking along about the same. It's been phenomenal."
Mr de la Haye said while locals made up the majority of visitors, they welcomed people from Auckland, Tauranga, Taupo, Wellington and Blenheim. And those commissions had come from buyers in Palmerston North and the capital.
He said that on the strength of what had happened last week he was a definite starter for next year.
"My work is pretty varied, a sort of mythical and Gothic mix, but I'll have a lot of other work on show next year. If it's anything like this year, I'll have to have more works for sale."
He makes many of his initial sculptures out of clay then takes moulds of some to reproduce them in concrete. Self-taught, he has only been doing this artform for the past four years.
He and Ms Earl were among more than 100 artists working in 64 studios who opened their doors to the public for Whanganui's biggest annual art event.
Open Studios co-ordinator Serena Siegenthaler-Brown said she had received positive feedback from studios and visitors. She said she had been worried about the impact the Womad festival in New Plymouth might have on the open studios event but that proved groundless.
"In fact, we had visitors from New Plymouth saying they'd come here because they wanted to get away from that," Ms Siegenthaler-Brown said.
She said firm data on the impact of the event would be available in the next few days.