Depends. Your degree is not considered "local". Normally for ministry, they have a salary range for each scheme. So having an honours matter because within your degree itself, they will also peg your salary accordingly. So for example, you are earning 3k outside now and you are joining the ministry. The ministry has a scheme for your uni, say, 2.5k - 4.5k. They can give you 3.5k because you have x class honours. If you dont have any honours, maybe they pay you 3.2k. This is just an example.

Just for your info, the local university that government considers are NUS,NTU,SMU and SUTD for now. They will have the same pay range, in a scheme. Universities like uniSIM, SIM, SIT will have a different salary within the range but same scheme as the rest. So if you are worried about not being in the same scheme as your colleagues, dont worry. The only difference is just the starting pay