The Hammers take on the Phoenix in Auckland as part of their two-match Football United Tour of the country on 23 July before tackling Sydney FC in Wellington three days later.
As part of his preparations for West Ham's visit, Merrick visited Chadwell Heath in the closing weeks of the 2013/14 season before watching the Hammers register a 2-0 Barclays Premier League victory over Tottenham Hotspur at the Boleyn Ground.
"My visit was about professional development and, since your boys are coming over to play against us, I thought it would be great to make contact and have a look at your pre-match preparations, game analysis and the final coaching session before a match," the 61-year-old told West Ham TV.
"I really learned a lot, actually. It's been a real insight into life at English Premier League level."
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