Reading : Western Philosophy VIII.10 "The Relief of Global Suffering"
Singer says that:
Most of the objections to this conclusion are of a practical nature (see presentation) but it seems more difficult to find errors in his reasoning (unless you don't accept his initial premises).
It might be argued though, that some of the rest of the passage contains statements which are matters of opinion rather than logical conclusions to Singer's argument. For example, Singer includes "over-population" in his list of "major evils": this is not qualified at all, although presumably he means "more people than can be supported by the resources available". Also, his characterisation of the consumer society as "people spending on trivia" suggests he may not be approaching this problem from politically agnostic position.
However, while some may take issue with some of Singer's justification for his argument, it seems to me that this is a bit like debating the colour of exhaust smoke from a passing enemy tank: the important thing is that a tank just drove past; we should be thinking what to do about the tank, not debating about whether I described the smoke coming out of the back as blue or grey.