Australia Post's planned sale of Sydney's historic GPO building to foreign buyers is "scandalous" and puts the complex at risk of neglect, the head of the National Trust NSW says.

Singaporean developer Far East Organisation is reportedly in the process of buying part of the Martin Place heritage site for $150 million. Architect and National Trust NSW branch president Clive Lucas, who specialises in restoring historical buildings, said the building was one of, if not the most, important colonial post…