Mr Park, 66, was last seen 10pm on Tuesday, January 3 when left the Recreation Hotel in Boulder and walked home with a work colleague.
Police say they have grave concerns for his welfare and the disappearance is out of character.
PerthNow understands that police concerns for Mr Park's welfare were heightened when the missing man's dog, known to be a beloved companion, was found alone at home.
It is believed detectives are also trying to determine whether anything has been stolen from Mr Park's Richardson St home, including the whereabouts of a wheelie bin believed missing from the property.
``We have serious concerns for his welfare, grave concerns given this is out of character for him and his friends and family have not spoken to himi,'' Detective Senior Sergeant Rod Wilde told PerthNow.
``We are conducting a forensic investigation at his premises given the fact that he hasn't been in contact with his family and hasn't touched his bank accounts in this time.''
Det Sen-Sgt Wilde declined to comment on a possible motive, but he said Mr Park was a regular at the Recreation Hotel and was well-known to staff.
Major Crime detectives have travelled to Kalgoorlie to assist Kalgoorlie detectives in their investigation.
Meanwhile, locals have set up a Facebook page in a desperate bid to find Mr Park, a miner who is described as being of good health.
``Still no news of Charlie's whereabouts,'' one post read on Monday. ``Can everyone please pause today and send your silent thoughts to his family?''
``They are so worried and the fear of the unknown is worse kind of fear...Even the smallest bit of information could be what brings the family the answers they are desperately waiting for.''
Anyone with information about Mr Park's disappearance is urged to call Crime Stoppers on 1800 333 000.
Boulder man's disappearance 'out of the ordinary'
Aja Styles- WA TodayJanuary 11, 2012
Kalgoorlie detectives hold "grave fears" that a missing Boulder man may have been the victim of foul play.
Major crime and forensic investigators are in Kalgoorlie to help local detectives, who say that the disappearance of 66-year-old miner Charlie Park is out of character.
"We hold grave fears for Mr Park's welfare sine no one has heard or seen from him since January 3rd. He's not been in touch with family or friends, which is highly unusual," Detective Inspector Rod Wilde said.
"We hold concerns for his welfare since it's out of character for him and we don't believe he's just wandered off and can't be found."
Mr Park has also not accessed any of his bank accounts.
A Facebook page dedicated to finding Mr Park also said it was "out of the ordinary" for Mr Park to disappear.
He was last seen on Tuesday night last week after walking home from the Recreation Hotel with a friend.
The 66-year-old father, and grandfather, has lived in Boulder for a great many years, with many people posting their concerns on the dedication page.
One person wrote: "This is such a shock to everyone who knows Charlie he is a man of habit and everyone knows that he often spoke to us at the pub and even offered his home to me a few yrs ago as a safe haven if I needed it, a man with a heart of gold.
"Always a polite customer and a funny bugger too we are all waiting to hear that your ok Charlie just wish there was more we could do to help.
"Our hearts are with his family at this time. Stay safe mate hurry home xx"
The page creator reassured concerned locals that police's stepped up efforts were procedural.
"At this stage the forensics is a formality with any suspicious missing person. Charlie is still missing," they posted.
"Please consider the family is very anxious and as soon as something is known I am sure they will let everyone know.
"For now can I ask that you keep them in your thoughts and consider they may need some private time to gather their thoughts.
"They appreciate all your comments of concerns and on behalf of the family I would like to thank everyone who has commented and sent hopes and wishes their way."