 Blamey proposed Mackay as a second choice but preferred Herring as he was much younger, and this was important in the taxing New Guinea climate.When Blamey relinquished command of New Guinea Force on 30 January 1943, he handed over temporary command to Mackay to enable Herring to go on leave.The period was a quiet one, with no major operations being carried out, and Mackay handed back to Herring and returned to command of the Second Army at Parramatta, New South Wales, in May 1943.