"With Robin Copeland returning to play in Ireland next season it will be an opportunity for him to impress during the training week, while some of the younger or less experienced players such as Rob Herring, Iain Henderson, Rhys Ruddock, Kieran Marmion and Felix Jones have turned in some very positive performances to earn spots in the squad."
A number of players currently injured or returning from injury will remain with their provinces to gain further recovery time or game-time.
They include Richardt Strauss, Donnacha Ryan, Roger Wilson, Tommy Bowe, Simon Zebo, Declan Fitzpatrick and Craig Gilroy. Some of these players may yet return for RBS 6 Nations matches.
There is also the injured group of Sean O'Brien, Stephen Ferris, Mike Sherry and Stuart Olding who will be unavailable in the longer term.
Ireland's opening fixture of the Six Nations is against Scotland at the Aviva Stadium on Sunday, February 2. Reigning champions Wales visit Dublin six days later and Ireland then travel to Twickenham to face England on Saturday, February 22.
Ireland's final home game of the Championship is against Italy on Saturday, March 8 before the team travels to Paris to take on Philippe Saint-Andre's French side on Saturday, March 15. Ireland's three home games at the Aviva Stadium are sold out.
The O2 Ireland Wolfhounds will play England Saxons in Kingsholm, Gloucester on Saturday, January 25 with a mixture of youth and experience likely to make up the squad selected for this match.
IRELAND EXTENDED 2014 RBS 6 NATIONS SQUAD:
Backs (20) -
Isaac Boss (Terenure College/Leinster)
Darren Cave (Belfast Harlequins/Ulster)
Gordon D'Arcy (Lansdowne/Leinster)
Keith Earls (Young Munster/Munster)
Luke Fitzgerald (Blackrock College/Leinster)
Robbie Henshaw (Buccaneers/Connacht)
Paddy Jackson (Dungannon/Ulster)
Felix Jones (Shannon/Munster)
David Kearney (Lansdowne/Leinster)
Rob Kearney (UCD/Leinster)
Ian Keatley (Young Munster/Munster)
Ian Madigan (Blackrock College/Leinster)
Kieran Marmion (Corinthians/Connacht) *
Luke Marshall (BallynahinchUlster)
Fergus McFadden (Old Belvedere/Leinster)
Conor Murray (Garryowen/Munster)
Brian O'Driscoll (UCD/Leinster)
Eoin Reddan (Lansdowne/Leinster)
Jonathan Sexton (Racing Metro 92)
Andrew Trimble (Ballymena/Ulster)
Forwards (24) -
Rodney Ah You (Buccaneers/Connacht) *
Stephen Archer (Cork Constitution/Munster)
Rory Best (Banbridge/Ulster)
Robin Copeland (Cardiff Blues) *
Sean Cronin (St. Mary's College/Leinster)
Robbie Diack (Malone/Ulster) *
Cian Healy (Clontarf/Leinster)
Jamie Heaslip (Dublin University/Leinster)
Iain Henderson (Ballynahinch/Ulster)
Chris Henry (Malone/Ulster)
Rob Herring (Ballynahinch/Ulster) *
David Kilcoyne (UL Bohemians/Munster)
Mike McCarthy (Leinster)
Jack McGrath (St. Mary's College/Leinster)
Martin Moore (Lansdowne/Leinster) *
Jordi Murphy (Lansdowne/Leinster) *
Paul O'Connell (Young Munster/Munster)
Tommy O'Donnell (UL Bohemians/Munster)
Peter O'Mahony (Cork Constitution/Munster)
Mike Ross (Clontarf/Leinster)
Rhys Ruddock (St. Mary's College/Leinster)
Devin Toner (Lansdowne/Leinster)
Dan Tuohy (Ballymena/Ulster)
Damien Varley (Garryowen/Munster)
* Denotes uncapped player