The West Ham loanee did not see eye-to-eye with Nigeria's previous coach.
Samson Siasia took over from Sunday Oliseh last month and one of his first actions as Super Eagles boss was to try and convince Emenike, and Lille goalie Vincent Enyeama, to renege on their previous international retirements.
However, he told the BBC the attempt had been unsuccessful:
"You can't force them to rescind their decision and we have to respect that.
"I felt they left under a cloudy circumstance. It was only an opportunity for them to reconsider their stance but it appears they've both decided to stick by their retirement."
Emenike will therefore be able concentrate solely on his club career - which may or may not be with West Ham in the long-term.
West Ham moved to address their striker shortage at the start of last month with a move to bring in Emenike until the end of the season.
The Nigerian arrived at the club on loan from Fenerbahce at the start of the month to provide cover in an area where injuries have been commonplace this term.
Emenike's previous loan deal at Al-Ain was cancelled to accommodate the switch and after a slow start he came to the fore in a recent FA Cup fixture with Blackburn Rovers and looks a good asset for the club.