A third man has been charged with attempted murder over the brutal shooting of a Sydney real estate agent in Melbourne's west.

The 29-year-old Irish national, who was living in Point Cook, was arrested at Melbourne Airport on Sunday about 9pm.

He was remanded in custody and will appear at Melbourne Magistrates Court on Wednesday.

It comes after Irish nationals Mark Dixon, 30, and Jack Harvey, 26, were arrested late last month at Broken Head in NSW over the shooting of Sid Morgan, a former detective who was shot in the face at a home in Spraypoint Drive, Point Cook, about 11pm last Thursday.