The annual payments have been made since the early 1980s and have never been declared to shareholders in Kingfisher's annual report.
Mr Whittaker, executive director, said last night that failure to notify shareholders was a mistake that would be rectified in the latest accounts.
The news may mean further embarrassment for the company, which last month underwent a boardroom shake-up when investors demanded action after dreadful profits results.
The bill for tax advice for Sir Geoffrey, chief executive, and his wife, Lady Valerie, was about £4,000 last year. Mr Whittaker said his own advice bill was roughly the same.
Kingfisher began paying Mr Whittaker's bill when he joined the company in 1982, and Sir Geoffrey's when he started in 1983. "It was part of the remuneration package arranged at a time when no executive would have touched Kingfisher with a barge-pole,'' Mr Whittaker said.
He denied that such payments to British executives were rare, but admitted they should have been disclosed. "It was a mistake. It was a lack of appreciation that they should go in the annual report."
Kingfisher's DIY subsidiary B&Q is creating 2,000 jobs, mostly part-time, following the opening of new stores.