A NSW woman has begged her sister, who hasn't been seen in nine months, to pick up the phone.
Ellen Wilson, then 54 and a disability worker, went missing from Ballina in the state's north last September, Elizabeth Crook says.
Her disappearance is not being treated as suspicious at this stage but police hold serious concerns for her welfare.
"I hope she is watching. I do love her. All my sisters love her," Ms Crook told reporters at the launch of National Missing Persons Week in Sydney on Sunday.
"I'm sure we'll understand what she is going through if she just picks up the phone."
Ms Wilson has not accessed her bank accounts or made any phone calls since September.
She was last seen at an ATM and was reported missing after failing to meet a friend and may still be travelling in her silver Subaru station wagon.
"We need the help of the public. We've got to the end of our inquiries," Detective Chief Inspector Cameron Lindsay said.
"While nothing at this stage of the investigation suggests foul play, we simply can't rule anything out."
The case is one of many being highlighted during National Missing Persons Week.
Adelaide man Michael Modesti, thought to have been murdered, was last seen in May.
The 33-year-old's death is believed to be drug-related but his family said not knowing what happened was "like living in the darkest of shadows".
"Words cannot describe the brokenness our family now lives with each day," they said in a statement.
Mr Modesti last spoke to his partner by phone and his car was found dumped days later.
"We strongly believe that there must be someone, or an isolated group of people, that must know something," his family said.
People with information on these or any missing persons have been asked to call Crime Stoppers on 1800 333 000.
