March 19 (Reuters) - Australian department store Myer MYR.AX on Wednesday reported a drop in half-year earnings, citing operational issues at its National Distribution Centre and a challenging macro-economic environment.

The retailer posted first-half net profit after tax of A$42.4 million ($26.97 million), a 18.5% decrease from the previous year.

($1 = 1.5718 Australian dollars)

(Reporting by Rishav Chatterjee in Bengaluru; Editing by Vijay Kishore)

((Rishav.Chatterjee@thomsonreuters.com;))