Gwent Police say a number of lines of enquiry are being pursued, but it is believed Nida may have had a disagreement at home before she went missing.
Assistant Chief Constable Paul Symes said there is nothing to account for her disappearance.
We know that Nida went out that Saturday evening at about 8pm to take the bins out without her purse or telephone and didn't return. We believe that she had a verbal disagreement within the home which possibly could have upset her and led to her leaving. There is nothing to account for her disappearance. Whilst we are pursuing a number of lines of enquiry, there is no information at this stage to suggest that she was picked up in a vehicle at all.
We have been working closely with Nida's family, local agencies as well as the community, to ensure we have all the information we need about Nida, in particular about her friends and lifestyle, to give us as much opportunity as possible to take the investigation forward and locate her. To go missing is particularly out of character for Nida and that, as well as her medical condition, makes me very concerned for her welfare.
Nida is of Asian-Pakistani appearance, with long dark hair, of slim build and five foot three inches tall. She was last known to be wearing blue jeans and a black top.
Anyone with information can contact Gwent Police on 101 quoting log number 448 28/12/13.
More top news
Dry across the country this evening with broken cloud and some late sunshine. Scattered showers expected tomorrow.
40,000 people are expected at the motorbike event in the capital this weekend.
The comedian visited the area in 1964 after apparently upsetting people with one of his routines.