Chief Executive Leung Chun-ying's first day at work yesterday saw members of his own administration call on him to address public concerns about illegal structures at his home on The Peak. The calls came as reports said four ministers and Executive Council members had illegal structures at their homes. New health chief Dr Ko Wing-man and Exco member Bernard Chan admitted having unauthorised structures. Chief Secretary Carrie Lam Cheng Yuet-ngor, along with Chan and fellow Exco member Cheng Yiu-tong, yesterday called on Leung to give a detailed explanation of the six illegal structures, including a glass enclosure and a basement, at his home. But Lam and Cheng both said in separate interviews that the presence of the illegal structures was a matter of negligence by Leung, and did not call his integrity into question, despite accusations that he lied. 'If it's not dealt with properly, it will pose difficulties to governance,' Lam, the former development chief, said. 'I will encourage, support and even advise the chief executive to explain it as soon as possible and avoid it being uncovered [bit by bit] by media reports.' Cheng agreed, saying: '[Leung] should come out to formally explain [the illegal structures] comprehensively ... or he will be dogged by it.' Chan admitted, after a report by Eastweek yesterday, that a check a week ago had revealed that a rooftop trellis and canopies on balconies, commissioned by his family, at his Happy Valley home were illegal. He said demolition had begun. Ko was checking whether the removal of a partition wall dividing his two flats in Beacon Hill had been unauthorised. His press secretary said an illegal glass structure on the roof was removed in May. Education Secretary Eddie Ng Hak-kim and Exco member Cheung Hok-ming had yet to respond to claims of illegal structures. Illegal structures are particularly sensitive for the new administration after a scandal centred on a massive illegal basement helped derail the campaign of Leung's election rival Henry Tang Ying-yen. Meanwhile, Democratic Party leader Albert Ho Chun-yan said the party would file an election petition to the High Court today if the documents were ready in time. The move is a challenge to Leung's election over allegations that he had made misleading statements about the illegal structures during his campaign. Leung yesterday agreed to face questions from lawmakers before the end of the Legislative Council term on July 17. The question-and-answer session may take place on Tuesday or Thursday next week, Legco president Tsang Yok-sing said.