Tony Blair is facing questions from Parliament's ethics watchdog over claims that he failed to declare a holiday with a powerful businessman with close links to the tobacco industry.

Sir Philip Mawer, the Parliamentary Standards Commissioner, has asked the Prime Minister why he failed to record a family holiday in the chateau of the billionaire businessman Alain Dominique Perrin in the Commons' register of interests.

The questions follow complaints from Tories because of M. Perrin's former role as chief senior executive in the French luxury goods firm Richemont, which owns brands such as Cartier and Dunhill, and also has a £3bn stake in British American Tobacco.

The Blair family's five-day holiday at Chateau Lagrezette in Caillac, which took place in 2002, was first revealed by The Independent on Sunday, leading to criticisms from some Labour backbenchers because of M. Perrin's links to the tobacco industry.

At the time, the Government was proposing a ban on smoking in public places. Labour MPs feared it could rekindle the controversy that engulfed Labour over the £1m donation by F1 chief Bernie Ecclestone just before ministers exempted motor racing from a ban on tobacco advertising.

Prompted by the Tory MP Chris Grayling, Sir Philip asked Mr Blair to explain why he had not entered the holiday in the Commons' register. Mr Blair insisted his friendship with M. Perrin is private and has had no bearings on his duties nor was there any conflict of interest.

Sir Philip accepted that explanation and seemed to agree that Mr Blair did not have to declare it. But according to reports in The Sunday Telegraph, the Commissioner has again asked Mr Blair for an explanation after being pressed to make further inquiries by Mr Grayling.

Under parliamentary rules, MPs are obliged to provide information of any "material benefit [which] might reasonably be thought by others to influence his or her actions".

During the family's stay at the chateau, Mr Blair spent one working day with the French Prime Minister, Jean-Pierre Raffarin. Reports quoted Mr Grayling as saying: "Although one day was spent on official business, I am not sure this would exempt him from having to declare it. I am not seeking to allege any impropriety ... but surely in the circumstances the Prime Minister would be bound by the rules to declare the hospitality?"

A Downing Street spokesman said Mr Blair's officials were talking to Sir Philip about the complaint and were co-operating. A spokeswoman said: "Anything that needs to be registered will be registered ... There is correspondence going on."