He said the doors on the machines cannot be shut from the inside and another person must have closed it.
"It is impossible for someone to close it from the inside and a key is required to start the machines."
Firefighters have dismantled machine doors to free children three times since 2015. "It must have been very frightening for the kids," Davidson said. "They can't open the door from the inside but as long as the power is left on, the door can be opened from the outside after about five seconds."
Davidson said he understood why someone would want to disconnect the power but the doors locked when the power was off.
Keys for the machines were issued at the Alma Rd Dairy, a block away from the laundromat on the corner of Carlton Ave.
In October 2015 a boy aged about 10 walked into the dairy and said he had shut his friend in a machine.
"He told me that his friend climbed inside and asked him to shut the door and then he couldn't open it to let him out," said Anastasia Zhang, whose family owns the dairy.
In September 2016, a 9-year-old girl climbed into a machine while her aunt and uncle were attending to their washing.
The girl said she did not know why she got inside the machine but said her brother had shut the door.
The children's uncle called emergency services and once again, firefighters dismantled the door to free the child.
"It shouldn't be necessary to dismantle the door," Davidson said.
"I will come to Whanganui and work with the fire service to find an easier way for them and for us but it will be a lot better for everyone if children are supervised in the laundromat."
Davidson said he has lost sleep over the incidents and hoped there will be no more.