"Most builders are busy and have a lot of work coming through but land is getting harder to find," Penn said.
"The [Whanganui District] council is working to bring more land on line but I think that's years away. Infrastructure is the issue for development. I think the council need to help and support us bring land on line for Joe Bloggs, the general public."
Large housing construction companies were buying land in bulk which was putting pressure on small building firms.
"Those who need 20-plus houses a year to survive are going to try to secure as much land as possible. There's a slower stream of sections available."
Penn said his own company was doing mainly new builds and a few renovations "and most people are the same".
"Whanganui doesn't seem to hit the peaks and troughs. It's not as volatile as other places. I'd like to see the activity keep on going but we can't sustain the number of sections needed. When it does slow down, the renovation work will pick up.
"It's a good strong market. There's lots of confidence. People are buying and clients are prepared to spend the money.
"Guys are turning away work. For my company, we're booked eight to nine months ahead. Clients are searching for professionals to build their houses and are jumping around trying to find a builder which tells you it's a good market right now."
A lack of skilled labour was an issue throughout New Zealand and most Whanganui builders were looking for qualified staff because of the amount of work they had on, Penn said.
"People are employing people to help out so guys are moving around between companies a bit.
"We're lacking qualified carpenters. Currently, training at Ag Challenge is providing new apprentices to the marketplace or they come straight from school."
The other training option at present was night courses in Palmerston North but Penn said he was working with Ag Challenge on the possibility of running night classes in Whanganui.