The BBC has said a total of five complaints were made about Russell Brand's behaviour while he hosted radio shows between 2006 and 2008.
Two of these complaints were made in the last two months, since a review of his time at the BBC was launched.
Those two complaints are understood to relate to his workplace conduct, and are not of a serious sexual nature.
The other three were made before he was publicly accused in September of rape and sexual assault, which he denies.
One was first made in 2019 and relates to a previously reported allegation of misconduct while on BBC premises in Los Angeles in 2008.
Two complaints were made during Brand's time working as a presenter for BBC Radio 2 and 6 Music.
The BBC's director of editorial complaints and reviews, Peter Johnston, is conducting the review into Brand's behaviour at the time, whether managers knew about any allegations, and what action they took.
Earlier this year, the comedian and actor was accused of rape and sexual assaults between 2006 and 2013 as part of an investigation by the Sunday Times, Times and Channel 4's Dispatches.
Brand strongly denied the allegations and said his relationships were "always consensual".
The investigation also included claims about his wider behaviour towards women and his workplace conduct over the same period.
The BBC announced in September that it was "urgently looking into the issues raised" by the allegations.
One claim was that Brand had teenage girls driven to his home via BBC cars. However, the interim update from Mr Johnston said: "Due to the passage of time the BBC's records of car bookings are no longer available.
"This means that we have not been able to identify the precise details of this or any records or details of specific journeys or bookings made for Russell Brand." He added investigations would continue.
In his update, Johnston said the review of Brand's behaviour was "not a straightforward task".
"For example," he continued, "the BBC did not maintain a centralised record of staff complaints regarding bullying and harassment (including sexual harassment) at the time."
He added: "Although my work is in no way complete and therefore I cannot yet reach any conclusions, it would appear that no disciplinary action was taken against Russell Brand during his engagement with the BBC in 2006- 2008 prior to his departure from the BBC."
In addition to the complaints made against Brand, Johnston said: "It is also clear from audience feedback that there was a wider concern about the tone and content of some of Russell Brand's shows."
Johnston said audience concerns related to the "general tone, topics and language" of Brand's radio programmes, adding that although these are outside the review's remit, he would consider whether they should have "raised alarms within the BBC".
The star has denied "very serious criminal allegations" and "extremely egregious and aggressive attacks", which he said he "absolutely refutes".
Although the alleged assaults are not said to have taken place on BBC premises, the claims raised questions for the broadcaster and the wider industry.
Channel 4, where Brand also worked as a presenter, is conducting its own internal investigation. There is also no suggestion that any alleged assaults took place on the channel's premises.
Another company, Banijay UK, has also commissioned its own investigation. Endemol, the production company behind shows Brand appeared on in the mid-noughties such as Big Brother's Big Mouth, was bought by Banijay in 2020.
He has also been accused of sexually assaulting an extra on a film set in a civil lawsuit filed in the US. Brand has yet to respond to the legal action.
Johnston encouraged anyone with relevant information to come forward, and said he hoped to provide substantive outcomes from his research in the New Year.