Police say understaffing led to inadequate monitoring of Tanya Day

Aboriginal woman Tanya Day said she was okay seconds before falling and hitting her head in a Victorian police cell, an officer has told an inquest into her death.

But police admit they did not physically check whether 55-year-old grandmother was alright as often as they should have, partly because of understaffing due to their Christmas party.

Ms Day died in hospital from a brain injury sustained from falling and hitting her head five times inside Castlemaine Police Station, after being arrested for public drunkenness on December 5, 2017.

Leading Senior Constable Danny Wolters was in charge of checking on Ms Day but says he was not worried when he saw her stumble drunkenly in her cell.

He told the Coroners Court of Victoria on Wednesday he saw a sudden movement in Ms Day's cell but did not see her fall.

"I can only describe it as a drunken stumble," he said. "It wasn't behaviour that concerned me."

The officer said he went up to Ms Day's cells at 4.51pm and asked her if she was okay and she replied that she was.

Const Wolters did not go into the cell and, seconds later, the Yorta Yorta woman was captured on CCTV falling and hitting her head on the wall.

When the officer went back about 45 minutes later, it was "same question, same answer".

This happened again just before 6.45pm, Const Wolters told the inquest.

After 8pm, he and another officer went inside Ms Day's cell for the first time and found a fresh bruise on her forehead, so they called the ambulance.

Const Wolters told the operator he'd seen Ms Day slip over about an hour before but it hadn't seemed to affect her.

Ms Day was soon in a critical condition and she died 17 days later from a brain haemorrhage.

Today, Const Wolters backtracked and said he didn't actually see her fall, contradicting earlier evidence from his colleagues.

Ms Day's level of drunkenness meant the officer was meant to physically check and rouse her every 30 minutes but he didn't.

Const Wolters instead checked on her every 20 minutes, alternatively through the cell window and using CCTV, partly because of staffing issues due to Castlemaine police holding their Christmas party that night and officers from nearby stations were filling in.

The inquest, looking at whether racism contributed to Ms Day's death, continues.