Recommendation Letters - Advice

I worked before in a project with a person who is now working in Australia as a
Senior IT Advisor in Government firm, he has 20 years of experience and know my work very well.

Can anyone recommend me to get Recommendation Letter from this person which strong my application?

Thanks a lot.

Can anyone please suggest me? Thanks

It is not clear what you’re asking about here. Of course, you can ask for a recommendation letter from this person.
The real question here is if it is just a recommendation letter confirming eligibility criteria (part of 10 pieces of evidence) or is it one of three reference letters required as well? If it is the latter I am not sure that Senior IT Advisor would be able to provide strong enough evidence. You probably will need to think of securing references from CTO, VP/Director of Engineering or similar position.

Usual disclaimer: I am not working for Tech Nation and I don’t (and not authorized to) represent Tech Nation

I am planning to attach this letter as a mandatory three Recommendation Letters.