EXPATRIATE civil servants have threatened to ''embarrass'' the Government if the Secretary for Civil Service, Mr Barrie Wiggham, cannot allay their fears about localisation. Mr Allan Roger, Localisation Committee's chairman of the Association of Expatriate Civil Servants, said the committee would make a formal request this week for a meeting before the end of the month. Mr Wiggham said last night he would agree to a meeting when he is approached. The committee will ask Mr Wiggham to consider giving expatriate civil servants a choice of extending their contracts on local terms, or finishing on expatriate terms but risk losing their jobs when the contract expired. The Senior Non-expatriate Officers' Association's main opposition to expatriate officers has been to their enhanced conditions of employment. But many expatriate officers have indicated they would be prepared to give up perks such as return trips to their country of origin, expatriate housing allowances, and longer holidays, in order to remain in the territory. ''We have always hoped this issue can be solved in a peaceful manner, but if this meeting cannot bear any fruitful results, we may embark on campaigns that may embarrass the Government,'' Mr Roger warned. Details of this campaign have not been finalised but they could also put their case to the legal profession, human rights group or legislators. Mr Roger said the localisation policy clearly violated the Bill of Rights, which stated there should be no discrimination because of a person's place of origin, his race or religion, but the association would reserve suing the Government as a strategy. He said the association would ask Mr Wiggham to change the current localisation policy to include the choice of terms immediately, or place a moratorium on the choice until the present review on the definitions of ''local'' had been completed. An internal study of the Civil Service Branch is looking at the possibility of redefining the term ''local'' based on factors including residency, language capability, whether the expatriates have taken British Dependent Territory Citizen passports, and whether they are members of Her Majesty's Overseas Civil Servants. The review will be completed in several months and it could lead to some overseas officers being designated as local staff. Mr Roger agreed that the Government should give preference to permanent residents for promotion or contract renewal.