Validity of the employment contract if based outside the UAE

Hi,

I was employed by a DMCC business but was based overseas (in Australia), not working in the UAE.

My employment contract was not registered with DMCC or MOHRE and I am looking to confirm what specific law requires UAE businesses to register employee contracts.

Is this requirement applicable to workers based overseas?

I'm in dispute with my employer and have been advised that my employment contract is not valid due to it not being registered.

Many thanks.