You first need to know the laws of the country where you "are". In the US, as long as you're not engaged in directly-regulated research (such as medicine), IRB approval is imposed on you via a contractual / employment relationship with an institution. Therefore, in the US, you are required to do what your employer requires of you. An institution may require that all research conducted using institution resources undergo IRB scrutiny. In the US, the institution would have no power to limit your independent research activities, but such assumptions of individual liberty may not hold elsewhere. Other countries may have other laws; if you're actually in China, you have to do what Chinese law requires of you, even if you're only occasionally in China. It does not matter, from the legal-enforcement perspective, whether it is difficult for you to pursue this question in Chinese, following prevailing cultural norms. You should therefore find someone who can give you honest and expert advice about IRB law (civil or criminal) in China. And just as it is in the US, you need to inquire of your employer what they require you to do (where the consequences of violating their rules could be getting sacked).
If you are only concerned with publication issues, you should inquire directly of relevant journals what their specific requirements are. Some journals do not raise the question at all (I only know by rumor that it's required in psychology). If a journal requires you to warranty something about IRB approval, you need to know in advance exactly what is required. While I assume that approval from Monash would suffice, you really should verify that that is the prevailing policy for journals in your field. In the worst case, if some journal requires IRB approval from each institution where you are employed while conducting the research, they just don't submit your work to that journal.