You can only work for local accounting companies if you know Spanish. Foreign degrees are NOT preferred over Argentine ones in the field. Its a different matter if you were transferred here by your company.
I am wondering though, who told you it was a good idea to come to Argentina looking for a job? The market here is bust.
Nicoenarg perhaps is right when talking about local accounting firms that only serve local clients (tax and perhaps audit of local statutory Argentine GAAP) or international firms in certain field (ie tax).
However, working for one of the big 4 firms having being transferred from outside, all things being equal foreign degrees are preferrable, particularly if you also have some experience and a CPA / CA qualification as well. Argentine public companies are transitioning to IFRS as of this financial year end 31/12/12 so IFRS experience / knowledge is fairly highly sought after.
But, as nico alludes to you have a few road bumps in the way and this is how I see it:
1) Most companies either are not hiring at all or have greatly reduced hiring.
2) Another and probably the most important is the spanish factor; I think it would be difficult unless you are here for specific client assignments or you find a company that has a special need that you fit, to find a decent job without being well proficient in the language, being that its not that hard to find professionals that speak a decent level of english that suffices what a company needs. In addition, dont underestimate the connection with other spanish speaking countries in the region, particularly given many multinationals have either pulled their ops from Argentina, are significantly downscaling or planning exits.
3) The work visa problem. I have a friend I met here that is Australian, has a good CV given he has an accounting/finance degree from Aust and has some years experience in one of the big banks in Aust, plus was ex professional rugby league player. He came with very little Spanish, but his father in law is very high profile at River Plate and has a lot of contacts. Anyway, he got a number of interviews but had the problem of not having a work visa. Its a bit of a circle, its difficult to get a work visa without a sponsor / work but to get work they want you to have a visa already. Anyway, eventually he got work with one of the big 4s, but he entered at basically a graduate level. I am fairly certain the grads take home about 4-5k pesos per month. Lucky his gf has an apartment and he has savings, otherwise I am not sure he would be still be here.
I dont mean to burst your bubble, but I am just not sure BA is the place to come and enter in to your chosen field and commence / continue a career, unless you are coming here from outside on a contract / transfer etc or you can work mobile with a computer. Much better destination for a holiday.
If you want any further info, send me a PM I would be glad to help where I can.