Band member Shane Lynch said a dispute with representatives of the estate of the late singer, who died in October 2009, means they are unable to include new material featuring the Dublin-born star on a 20th anniversary CD.
"We'd love to use his vocals, but it's not so simple. Apparently, even though we were in a band with him for 17 years, we can't use his voice," he said. "When Stephen died we were in the middle of making an album. The last thing we could have done was continue after losing him. But he is very much alive on those songs."
However, Boyzone hope Gately's representatives will allow them to use a hologram of the singer on their anniversary tour, planned for later this year.
Solicitor Gerald Kean, who represents the Gately family, said his clients "were unaware of any dispute" and had not been contacted regarding the use of Gately's voice on the next Boyzone album, or the use of him as a hologram in live concerts. But sources close to Boyzone have spoken of tensions between the band and Gately's husband, Andy Cowles.
Attempts were made last night by the Irish Independent to contact the businessman, who married Gately in a civil partnership in London in 2006, but he did not respond.
On their last tour, Boyzone members Lynch, Ronan Keating, Keith Duffy and Mikey Graham shared their memories of their late bandmate with the crowd. At another point in the concert they asked the audience to sing the part once performed by Gately on Boyzone hit 'No Matter What'.