(ShareCast News) - Sportswear retailer Sports Direct issued a statement on Friday defending the way it treats its staff following a damning report in the Guardian. The company said criticism of the way it treats its staff was "unfounded" as it announced that founder and deputy chairman Mike Ashley will personally oversee a review of all agency worker terms and conditions to ensure the group meets its legal obligations and provides a good environment.Last week, the Guardian reported that workers at Sports Direct's Shirebrook warehouse were effectively being paid less than the minimum wage.The paper's undercover reporters found the retailer's workers were also being subjected to a regime of searches and surveillance, with many employees too afraid to take time off work.Sports Direct hit back at the Guardian allegations on Friday, saying the warehouse tannoy was not used to "harangue" or "name and shame" staff, adding that it does not penalise its staff for being ill.It also pointed out that all employees, agency workers and visitors, including executive management and board members, are subject to random searches on leaving the Shirebrook warehouse.Responding to allegations in the paper that some local primary school teachers were allowing pupils to remain in school while ill and return to empty houses, the company said it was "not aware of any occasions on which sick children have not been able to be collected from school by their parents".Sports Direct said it allows staff time off to look after dependants in such circumstances."Sports Direct always seeks to improve and do things better, listens to criticism and acts where appropriate."At 0825 GMT, shares were up 0.4% to 578.5p.