Kingon is one of the key witnesses billed to testify before the Nugent Commission, tasked to probe governance and administration at the revenue service since the appointment of Moyane.
The commission, chaired by retired judge Robert Nugent, has lined up various witnesses from today until next week.
One of them is Barry Hore, the former Sars chief operations officer (COO), who was accused of having too many powers while at the revenue authority.
Kingon is due to testify on Friday. He is one of the witnesses who had made formal sworn affidavits to the commission detailing several wrongdoings during Moyane's tenure.
In July he wrote a letter to the commission informing it about an alleged illegal trip undertaken by Moyane to Russia in October last year.
Kingon said Moyane wrote an urgent request to the then finance minister, Malusi Gigaba, to authorise his trip to Russia, but he allegedly failed to give details, as required by Sars Act.
Moyane apparently told Gigaba that he was urgently meeting with the head of the Russian revenue authority but failed to give details of the trip.
According to Kingon, the trip was illegal as Sars’ international relations unit was not aware of it, and Moyane failed to provide the unit such details even after his return from Russia.
Gigaba, when he appeared before the commission in August, confirmed that he authorised the trip because an impression was created that it was urgent.
He, however, asked the commission to recommend disciplinary action against Moyane for his failure to disclose details of the trip.
According to evidence before the commission, Hore - who is expected to testify on Thursday - was allegedly Moyane's target as he had more powers as COO.
When Moyane was appointed, he stripped Hore of his powers, as most of the Sars units, including the large business centre, reported directly to him. The centre's primary duty was to ensure that multinational and big local companies were tax compliant.
After Hore's resignation, the commission heard how smuggling of cigarettes, abalone and alcohol, as well as the illicit flow of money, increased in South Africa.
The commission heard that the flow of illicit goods was precipitated by the new Sars operating model introduced by Moyane.
According to the evidence, Moyane was advised by Bain Consulting Agency, but that advice had severe consequences for Sars as big companies and multinationals began failing to comply with their tax obligations.