"We don't know but we think he might have gone out on a spiritual journey of some kind - he's quite inclined in that way."
Mark had flown from Wellington to assist.
Huria's stepmother, Lynell Huria, said the family was extremely worried.
"We don't really know the current status apart from what the police have said to everyone through the releases in Perth.
"The family is really worried, really worried about him and hoping he turns up soon."
Police and SES volunteers have been searching in nearby Upper Swan where a woman thought she might have struck a pedestrian on Monday night.
Despite searching the area at the time no one was found near the road.
Huria's white ute was subsequently located in Ellenbrook but the 23-year-old remains missing.
"The search for Michael will continue throughout the day and will perhaps conclude early this evening," a WA Police spokeswoman said yesterday afternoon.
"Assessments will then take place regarding any future searches."
Upper Swan is five kilometres east of Ellenbrook in Perth's outer northeastern suburbs.
Huria was believed to be wearing a white shirt, blue shorts (possibly denim) and was not wearing shoes.
