Tennant Creek is searching for answers about why a "respectful, friendly and bubbly" Aboriginal mother died in the police watch house, more than 24 hours after her Christmas Day arrest.

The 44-year-old was found unresponsive inside the outback town's watch house on Saturday, almost 30 minutes after CCTV showed her falling to the ground, according to police.

The ABC is not identifying the woman while police continue to inform family members of her death.

But her loved ones in Tennant Creek have described her as a well-respected, long-term community member who "always greeted people with a smile".

Tributes of flowers have been laid at the Tennant Creek Police Station for the Aboriginal mother. (ABC News: Marcus Kennedy)

She was remembered as a hardworking and devoted mother, who was respectful, friendly and bubbly.

The woman was arrested for aggravated assault on Christmas Day and taken into custody at about 6pm.

NT police said they conducted routine, half-hourly checks on detainees in the watch house.

She was discovered unresponsive during one of these cell checks at 1:03pm.

Police said officers had conducted a cell check at 12.30pm and it was at this next scheduled check that she was found unresponsive.

"We reviewed the CCTV and at 12.34 she was in the cell alone and was seen to fall to the ground," Acting Assistant Commissioner Malley said at a press conference on Sunday.

The watch house she died in had no custody nurse, unlike watch houses in Darwin, Katherine, Palmerston and Alice Springs. (ABC News: Marcus Kennedy)

Woman suffered severe heart condition

NT police said they believe the woman suffered a medical episode inside her cell.

A post-mortem examination will be held today in Alice Springs to confirm her cause of death.

Multiple sources confirmed to the ABC the woman suffered severe health issues associated with rheumatic heart disease (RHD) — a potentially deadly condition caused by repeated streptococcal infections — which forced her to give up work several years ago.