HONG Kong Dissident Lau Shan-ching said Hong Kong officials have failed to clarify whether he was eligible to stand for election and he would ask the ombudsman to investigate. Mr Lau, who served a 10-year jail term in China for ''counter-revolutionary'' activities, yesterday went to the Registration and Electoral Office to see whether he could legally stand for office. The dissident, who wants to run in next year's district board polls, said he was not sure whether he had ''ordinarily resided'' in the territory for 10 years before nomination, because he was in a mainland jail for most of that period. Mr Lau said he had been trying to find out from the Government for six months, without success. He quoted Shirley Leung Oi-yiu, acting deputy chief electoral officer, as saying the Government was flexible in defining ''ordinarily resided'', but the final interpretation would be made by a district officer in charge of election affairs. But Mr Lau said he was dissatisfied because she was unable to say whether an appeal would be possible. According to law, an appeal can be taken to the High Court only if a candidate or 10 electors questioned the results within two months of the election. The liberal activist said he could not lodge an appeal when he was not recognised as a candidate. ''It deprives me of my civil rights and it is most unfair to me,'' he said. Mr Lau also demanded an explanation from the Deputy Chief Electoral Officer, Lai Kwan-tat, as to why he was ruled ineligible to stand for election because of the residence restriction. Miss Leung said that was a misunderstanding, but Mr Lau said he would appeal to the ombudsman.