“公务卡” has been used quite broadly in China lately. It can refer to “corporate card” when the card holder is any company's employee who is using it for related business expenses. In this case, it can also be called “公司卡", "企业卡" or "商务卡" in Chinese.

But when “公务卡” particularly means the type of credit cards that are used by government employees for work-related expenses, as stipulated by the government, there seems no fixed translation yet. The translation used include: official card (this one sounds a bit funny because it implies there might be one type of unofficial card too), official business card (this one has the same syntax error, and even worse, using "official" & "business card"), public affair card, public service card, and work-related expenditure card.

Please see the following references regarding “公务卡”:

“标准公务卡是我行发行的VISA 品牌双币种公务信用卡，卡片正面印有“ Corporate Card”字样及单位英文名称，由单位承担还款责任的公务信用卡，您可在贴有“银联”、“威士”受理标识的商户及自动柜员机上使用。”
http://creditcard.cib.com.cn/card/ProductsInfo/dutySeries/vi...

“针对单位常差旅人员设计的，可以根据需要选择单位承债或个人承债。单位承债必须由单位统一还款，个人承债可以由单位统一还款，也可以由个人自行还款。”
“It is especially designed for the personnel of the company, who is frequently on business. The company or the individual shall undertake the credit card debts. If the debts are to be undertaken by the individual, either the company or the individual may pay off the debts.”
http://www.cardcmb.com/business/tf.html


"我区推行公务卡制度一些问题的探讨"
"Discussion on the Implementation of Corporate Card System in Guangxi"
"为了顺应公共财政改革,提高各级预算财政财务管理水平,我区推行了公务卡制度,通过我区推行公务卡制度改革的现状和存在的问题,以及解决问题的方法和建议进行讨论,以促进公务卡制度改革的不断完善和可持续发展."
http://d.wanfangdata.com.cn/Periodical_gxczgdzkxxxb200902017...

"...gradually adopts the practice of using work-related expenditure cards for payment and account settlement." (China's National Defense in 2008)
"...逐步推廣公務卡支付結算" (2008年中國的國防)
http://74.125.113.132/search?q=cache:FGhudnB2zjMJ:big5.china...

Caroline, since you are an English native speaker, maybe you can come up with a better translation for us. :)