Gately was just 33 years old when he died of an undetected heart condition in 2009, and the remaining Boyzone members were plunged into mourning.
Last year (12) they unveiled plans for a special album and tour in 2013 to mark their 20th anniversary in music, with many new tracks set to make the record.
Gately features on several tunes, but Lynch has revealed that a dispute with the late star's estate over who owns the rights to his vocals means Boyzone cannot use the songs.
He tells Britain's Daily Star Sunday, "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. But there you go.
"When Stephen died we were in the middle of making an album. The last thing we could have done was continue after losing Stephen. But he is very much alive on those songs."