Cub - The term semi-state is often bandied about loosely. Most semi-state agencies are commercial organisations where the Govt is ultimately the shareholder. They normally set their own employee terms & conditions, e.g. ESB, Bord na Mona, Dublin Airport Authority, Dublin Port etc. Some people use the term semi-state to refer to any govt agency, including statutory bodies like FÁS, Comhairle, Equality Authority. Some people get mixed up and refer to some charities as semi-state. These are often largely Govt funded but in fact are independent bodies, e.g. NWCI, Enable Ireland etc. Are you sure that you are actually in a semi-state organisation?
I'm guessing that there are not too many 'semi-state agencies' that have merged with other bodies, so be mindful that others may well be able to identify the organisation concerned.
On the original issue, have a think about the rights and wrongs of this issue. If the organisation is publicly funded, surely it is fair enough for the organisation to find the most cost effective way of doing this - presumably the pool cars. Perhaps your complaint should be about why some people are still allowed to claim expenses while you are not. Make sure you have your facts right - things are not always what they seem. I remember somebody making a complaint about why some colleagues where getting expenses to drive to some events/meetings, while others had to use public transport. It turned out that they weren't getting mileage expenses, they were actually getting the train fare, and using that to cover their own petrol costs.