If you search carefully based on the link I provided early, you
will find that there are number of schools offered ACCA :
http://www.cpe.gov.sg/cos/o.x?c=%2Fcpe%2Fpeis&func=courses&ptid=401&kw=acca&pg=1
As long as the accounting qualification are supported and
regulated by the Institute of Certified Public Accountants of
Singapore (ICPAS), you should have no problem in getting an
government job.
For your info, getting an Certified Public Accountant (CPA)
qualification is even harder than ACCA, still you will
have an advantage over ACCA student (since you might also need an
degree to qualify). You think it is manageable and you can score
very well, you might like to give it a try : http://corp.icpas.org.sg