Robyn McSwain is pleading with the public across the region to think back to the past month and try to remember if anyone has sighted her sister-in-law Kay.

Kay, from Werribee, was last seen across the Grampians region.

Ms McSwain has spent weeks on the phone and on social media trying to help her family try to find the missing 46-year-old.

"I was talking to my friend and she told me that she might have gone somewhere, where she feels safe," she said.

"She has always said she liked Halls Gap. She rang my brother and he came up and caught up with her in Halls Gap and said something wasn't quite right.

"He pointed out to me that it wasn't really 'Kay'. Kay is an organised person with matching luggage and always presented well.

"She stayed in accommodation in Halls Gap - he hoped she would get some sleep and relax. He had to go back to work and then he tried to call her and kept getting her voicemail.

"Their daughter got in touch and was saying she kept getting voicemail as well. That's when the red flags started to occur."

Victoria Police has said Kay was last seen at a bus stop outside a Stawell motel at about 9.15am on Tuesday February 2.

Kay was last seen wearing a yellow t-shirt, blue jeans and was carrying a grey backpack and shopping bags. She is 172cm tall with a medium build and short brown hair.

Police and family hold concerns for Kay as it is unusual for her to not make contact with family.

"We know she had access to some amount of money but money doesn't last," Ms McSwain said.

"We've been posting on social media and my brother went to Halls Gap to start looking for her.

"We think she might be looking for a job - she did say there was lots of jobs in regional Victoria.

"We just hope that anyone has seen or heard from her can just get in touch and say she is ok.

"Kay, - we're worried. We don't need to know where you are or what you are doing, we just want to know you are ok."

Anyone who has seen Kay or has information on her whereabouts is urged to contact Stawell Police Station on 03 5358 8222.