Spokesman Peter Saunders said the corporation's attitude to the Harris case mirrored that taken with serial pedophile Jimmy Savile and jailed TV presenter Stuart Hall.
Watch: Rolf Harris in court over 'sex assaults'
"Harris, like Savile, like Hall, was part of a corporation that helped cover up institutionalised abuse," he told British tabloid The Sun.
"The BBC has to come clean to expose what has gone on."
Mr Saunders said the BBC was "almost aiding the abusers" and "they need to lance this horrible boil and get it out there".
However, a spokesman for the corporation said the Harris convictions "do not relate to the BBC".
"We already have the Dame Janet Smith review which is making an impartial and independent investigation into the past culture and practices of the BBC during the period Savile worked for the corporation," the spokesman said.
"And, related to that, we commissioned an independent assessment of our current child protection and whistleblowing policies which will report later in the year."
The Dame Janet Smith review was commissioned to examine how Savile carried out a decades-long campaign of abuse.
BBC producer Tina Fletcher-Hill worked alongside Harris on Animal Hospital and then Rolf on Art. She appeared as a defence witness during his eight-week trial, describing the star as affectionate, kind and honest.
"He greets people with hugs, that's just Rolf," Ms Fletcher-Hill told Southwark Crown Court via video-link in early June.
"(But) I never witnessed anyone pulling back or feeling uncomfortable with his tactile nature."
Rolf Harris's TV career begins
Harris headed to London in 1952 to study art but instead got a break with the BBC doing children's TV.
He initially had a five-minute spot with a puppet called Fuzz on Jigsaw.
The performer signed with the BBC in 1954 featuring on Whirligig. In 1967 he started the Rolf Harris Show which, in varying formats, became a light entertainment staple for more than a decade. In the 1980s he hosted, again on the BBC, Rolf Harris Cartoon Time.
For 10 years from 1994 he hosted Animal Hospital, which five times was voted Britain's most popular factual entertainment show. It was followed by Rolf on Art, the most watched arts program in British television history.
Star Portraits with Rolf Harris screened in the mid-2000s. The BBC in 2005 commissioned Harris to paint a picture of the Queen to mark her 80th birthday. That portrait is now missing.
But Harris's regular artworks could suffer an even worse fate.
One gallery owner in Lincoln, 200km north or London, has vowed to destroy five works.
"It's virtually valueless," Nigel Robertson said. "I think they will be destroyed."
Auctioneers in the UK say the Australian's art has plummeted in value by 90 per cent following his conviction early this week.
Australian of the Year claim "not correct"
Meanwhile, Australia Day Foundation chairman Philip Aiken has labelled as "not correct" a story that Harris was set to be named Australian of the Year in the UK in 2013.
News Corp reports Harris was stripped of the honour "days before the January 26 ceremony" due to then unreported allegations against him.
But Mr Aiken told AAP while Harris had been nominated "we never formally offered him that role".
The Queen's milliner of 34 years, NSW-born Frederick Fox, was always going to be honoured in 2013, the chairman said.
"Freddy Fox had been nominated and told he was going to get the role, not days before but months before."
Harris will be sentenced, and almost certainly jailed, on Friday, UK time.
The one-time royal favourite is the second person to be convicted under Operation Yewtree, which was set up in the wake of the Savile scandal. Publicist Max Clifford in May was jailed for eight years for indecently assaulting four young women between 1977 and 1984.
- AAP
