Ms Hoffman-Tamm's sister, Jan Donlan, who was at the press conference, said the disappearance was completely out of character.
"She's gone off to have a good time sometimes but never anything like this. We've always known where she was," said Ms Donlan.
On the day she disappeared Ms Hoffman-Tamm had spent the afternoon at her sister's house, across the road from her own.
Ms Hoffman-Tamm returned to the home she shares with her partner before leaving on her red mountain bike,
saying she was going to visit a friend who lived about 1km away.
There have been no confirmed sightings of her since then.
Ms Donlan said the family, including her sister's two adult children and three grandchildren, were extremely worried.
"We're all trying to cope, we just want her home that's all."
She said she was "holding on" as well as she could, but it was hard not knowing what had happened.
"She would never be this unkind to the family," Ms Donlan said.
She said her sister just loved helping people.
"Anything anyone needs she's there to help, whether it be doing people's gardens, mowing lawns, just helping people out. She's a very generous person."
Mr Smith said Ms Hoffman-Tamm was well known and liked in the area and was often seen out and about on her bike.
"She's known to help out people in the community . . she's considered to be the neighbourhood watch for her street."
He said she was described as happy and in a "very good head space" when she left home and there was no indication anything was wrong with her health.
Mr Smith would not comment on whether she had her mobile phone with her, but confirmed it had not been used since November 7. He said she was not believed to have had access to any money since that time either.
Ms Donlan said she had a message for her sister.
"Michelle, wherever you are love please come home. We miss you, we love you and we can't cope much further than this."
