In November one of Federal Parliament's most senior security officers used his finger to taste a suspicious lump of white powder to confirm it did not pose a safety threat to the building.

Key points: Vision of senior official's actions which occurred near public cafe disappeared

Vision of senior official's actions which occurred near public cafe disappeared Documents obtained by ABC indicate HAZMAT team should have attended scene but this did not happen

Documents obtained by ABC indicate HAZMAT team should have attended scene but this did not happen The official, Graeme Anderson, said substance was sugar

The unusual actions of the Department of Parliamentary Services (DPS) assistant secretary Graeme Anderson have raised eyebrows inside the corridors of power and prompted numerous questions in Senate estimates.

Many Parliament House guards remain bewildered by their boss's actions, and it is now claimed crucial security camera vision of the incident which occurred near the public cafe has disappeared.

But DPS officials have denied those suggestions in Senate estimates, under questioning from Labor senator Kimberley Kitching.

Six months on from the incident, the ABC has obtained a copy of Federal Parliament's "Operating Policies and Procedures" for "White Powder" security incidents, which details the ACT Fire Brigade's four-level classification system that grades threats in ascending order from Type 1 to Type 4.

According to the Security-in-Confidence document, a "Type 2 incident" involves a "suspect item or security incident where white powder is evident but the item is not accompanied by a specific threat, for example: 'a powder out of place'".

The manual also makes it clear that "in the ACT, Type 2-4 incidents require the attendance of the ACT Fire Brigade's Hazardous Material (HAZMAT) team in accordance with the ACT emergency response plan" — something which did not occur during the November episode.

'Powder out of place' footage deleted early, senator told

In February during Senate estimates, Senator Kitching grilled Mr Anderson on whether he had observed correct protocol, because anthrax has neither taste nor smell.

"You made an assessment by tasting it," she asked Mr Anderson, who responded: "Correct.

"I handled this incident in exactly the same way it would have been handled in the Australian Federal Police," Mr Anderson added.

"My assessment is based on the evidence available to me."

Mr Anderson told Senator Kitching there was no evidence it was suspicious, he said it was sugar on the balustrade, near the cafe.

Senator Kitching challenged him on whether it was actually near the cafe.

"It depends on your definition of near," he said.

Several days later, the former AFP officer wrote to the committee to clarify his evidence.

"The substance was only tasted after I had already determined that it was a Type 1 non-suspicious incident," the assistant secretary explained.

Senator Kitching said she would be demanding the full facts during this week's Senate estimates hearings.

"Whistleblowers within the department report that the footage of the 'powder out of place' — including footage of the head of the security branch notoriously tasting an unidentified white powder — was deleted early," Senator Kitching said earlier.

"If this is the case, perhaps the department can explain why this particular day of all days was the one instance in the past 18 months where footage has been deleted earlier than is normal.

"It is hard to believe that it is coincidental that there were reports in the media about the white powder incident and lo and behold this footage was deleted contrary to normal security protocols."

But in pursuing the line of questioning, DPS officials said they did still have copies.

"The footage hasn't been deleted," the assistant secretary of the department's building and security division, Paul Cooper, replied.

Senator Kitching then asked whether it was possible to see the vision, which Senate President Scott Ryan said he would take on notice.

The Department of Parliamentary Services recently clarified that security vision, which is automatically recorded in the building, is retained for approximately eight weeks, and that there are "no known incidents" since January 2017 where footage has been deleted before the end of the retention period.