Conservative co-chairman Baroness Warsi who is from Dewsbury, has denied failing to register business interests as she faced fresh allegations of breaching House of Lords rules.
The peer, whose expenses claims are being examined by a watchdog, insisted she had stuck by the rules for declaring shareholdings and directorships.
She was responding to a Sunday Telegraph report that she failed to declare a controlling stake in a spice manufacturing firm with the House of Lords authorities.
The newspaper said February accounts for Rupert's Recipes showedBaroness Warsi held 60% of its shares - sufficient to require a public declaration.
It said she was also listed as a director of the firm from February 2009 until July 6 2010, two months after she entered the Cabinet.
Sources suggested the shares were transferred into her name for a shortperiod only and were then passed into the hands of her husband.
They also said there was no requirement to register unpaid directorshipsbefore a strengthening of the upper house rules last year.
In a statement, Baroness Warsi said: "My shareholdings and, beforebecoming a minister, directorships have at all material times been disclosed asrequired on the Register of Lords' Interests and to the Cabinet Office and on theregister of ministerial interests."
Labour also raised questions about the presence of business associate Abid Hussain on an official trip to Pakistan by the senior Tory.
Shadow cabinet office minister Michael Dugher compared the case withthat of Liam Fox - who quit as Defence Secretary after his relations with alobbyist breached the ministerial code.
"This looks like the Liam Fox/Adam Werritty case all over again -with ministers allegedly being accompanied on official trips by their private business associates," he said.
"Baroness Warsi has urgent questions to answer: were House of Lordsrules broken in this case?
"What was Mr Hussain doing on an official Government trip in thefirst place?
Was he security vetted and was his presence cleared by the Cabinet Secretary or my Number 10?
"After his reluctance to take action against Jeremy Hunt, David Cameron now needs to show he is prepared to make sure his ministers show the highest standards of behaviour."
Baroness Warsi said: "Neither I nor the Conservative Party nor theGovernment has ever met the costs of foreign visits by Abid Hussain."
On Tuesday, she asked Lords Commissioner for Standards Paul Kernaghan tolook into the claims about her expenses. She denies any wrongdoing.