EPL finishes on 16 May. Nations Cup is from 29 May. So camp will be much shorter for those in Europe. Probably 9 days
It will be complicated getting several players released due to club commitments in late May (even early June in Tuiloma's case).
Worst affected will be Bill Tuiloma (Strasbourg's last game is June 4), Marco Rojas (Swiss league finishes May 25), Marinovic (Unterhaching's last game May 22) and Brockie and Boxall (South African season finishes May 21). Cutting it pretty fine for NZ's first game in the OFC Nations Cup on May 29. (See below for dates of last game of the season for all major All Whites players)
It will depend on negotiations between NZ Football and the clubs and to what extent NZ football want to enforce the strict letter of FIFA rules around the release of players for FIFA-sanctioned tournaments like the OFC Nations Cup.
Clubs only have to release players the Monday morning of the week before the tournament which starts on Saturday May 28 (so strictly speaking, clubs only have to release players five days before this tournament).
The relevant FIFA rules:
http://www.mishcon.com/news/briefings/internationa...
"For a final competition players must be released and start to travel to their national team no later than the Monday morning of the week preceding that of the start of the relevant final competition, and must be released by their association the morning of the day after their last match of the tournament."
http://www.fifa.com/mm/document/affederation/admin...
f) Final competitions
"In accordance with Article 36 Paragraphs 2b) and 5c), if a player is called up, he must be released to play in the final competition organised by FIFA or a confederation and held in a period fixed/set in the calendar. In this event, the period of release shall be 14 days."
The last English Championship fixtures are on May 8 (Wood, Smith, Cameron, Tzanev) three weeks ahead of the OFC Nations Cup.
Last National League (Southport) fixtures May 1 (Crocombe)
The last EPL fixtures are May 16 (Reid)
Last St Mirren fixture, Scottish Div. One is April 31 (Howieson)
Last Greek fixtures (PAS Giannina) April 16 (Tzimopoulos)
Last Dutch Eredivisie games are May 7 (Thomas)
The last Swiss fixtures are May 25 (Rojas)
The South African League finishes May 21 (Brockie, Boxall)
Last Unterhaching, Germany fixture is May 22 (Marinovic)
Scandinavian leagues start early April (Keat, Henderson) but those guys seem out of favour anyway.
If NZ football doesn't push to have them released early, some players will be available for only approx one week or less of All Whites May camp in bold:
Moss, Marinovic, Crocombe, Tzanev, Doyle, Reid, Boxall, Smith, Fenton, Roux, Tzimopoulos, Thomas, McGlinchey, Tuiloma, Cameron, Howieson, Payne, Wynn, Brotherton, Hudson-Wihongi, Rojas, Barbarouses, Lewis, Wood, Brockie, Smeltz,