He believed someone may have dropped something through the hole to start the fire.
Nothing had been stolen from the house, and there was no mains power connected.
Steve said he felt concerned the blaze was the result of a possible vendetta and negative feeling towards his activities as a developer in the town.
He was also concerned someone may resent that he is originally Australian, even though he has been working in the Horowhenua district for more than four years, and in New Zealand for 11 years.
His Wellington-based company was involved in building or owning multiple rental properties in Levin, including relocated houses and new builds.
"I think it's intentional, and I've been getting s**t for weeks," he said.
He said local contractors had told him some in the community were questioning why he moved the house there. He had also been made aware of derogatory and racist comments on social media after he felled a large tree on one of their properties.
He felt comments had been directed at him and his nationality personally.
"I've noticed a few of the ... comments on Facebook have been discriminating against me, more than the jobs," he said.
Steve said he and his Wellington-born wife had both noticed an decrease in tolerance in New Zealand over the last five years.
"Racism in this country has gone to another level," he said.
The home was only a fortnight away from being ready to be rented out, which Steve said was another blow for a town with a rental housing shortage.
"WINZ have so many people that need housing," he said.
Steve said he had also had six break-ins at his properties in the last three years, with tools stolen.
"Levin needs to sort its bad crime out, because it's going to stop the population growing," he said.
"The police need more resources."
However, he said he planned to stay positive and didn't have any quarrels with anybody.
"When [people] try to attack you and put you down, they're trying to win," he said.
"The way I look at it, when something like that happens, you get up and you have to go forward."
A police spokesperson said the fire was reported at about 3am.
"Police have attended the scene, and then commenced a scene examination alongside a fire investigator," the spokesperson said.
"A scene guard was in place ... and detectives have attended. At this stage, the fire is considered unexplained, and inquiries are ongoing."