How hard is it to get a government job if you did not graduate with good grades but is a student from one of the big 3 Unis?

I have second lowers from NUS.
Didn't get into a government job upon graduation, but after 3 years in private, manage to get in the very same type of job in the government. And the interviewers didn't ask about grades, only have to submit the grades to HR.

Hi, there is always ample vacancies in government sectors, considering it make up of signicfiant portion in the public or civil sector. Provided with the SGunited jobs scheme, there is much more opportunity. That being said, it also depends on your apply role and job skill match. Local university will have a good chance too. cheers!