Martin O'Neill will lead the Republic of Ireland to Euro 2016 with his future as manager shrouded in mystery.

O'Neill has yet to sign a new contract with the Football Association of Ireland despite indicating he is keen to stay on for the 2018 World Cup qualifying campaign.

That has opened up the possibility the 64-year-old might wait until after the European Championship in France before deciding whether he wants to return to a lucrative job with one of several interested clubs.

O'Neill turned down an approach from Leicester before Claudio Ranieri was hired last year and has admitted he misses the day-to-day club routine.

After enhancing his reputation by guiding the Republic to the Euros with a play-off victory over Bosnia, O'Neill finds himself in demand from several teams with which he has strong emotional ties.

Nottingham Forest chairman Fawaz Al Hasawi has reportedly offered O'Neill carte blanche to run the English second tier club as he sees fit in an attempt to convince him to take the job.

Al Hasawi's volatile reputation and the team's recent struggles will not help their pursuit of O'Neill. But as a former Forest midfielder during the club's European Cup and top-flight title winning years under Brian Clough the City Ground retains fond memories for the Republic boss.

It will also be fascinating to see if Aston Villa's relegation to the Championship dissuades O'Neill from returning to a club that has gone downhill dramatically since his four-year reign ended in 2010.

Villa narrowly missed out on Champions League qualification under O'Neill's leadership and reached the 2010 League Cup final before the coach fell out with owner Randy Lerner over a lack of investment in the team.

With Lerner reportedly close to selling, O'Neill might be lured by the task of restoring the storied club to their former glory.

And there is also a familiar and tempting vacancy north of the border after Celtic manager Ronny Deila announced he will step down at the end of the season.

After making his managerial reputation by turning Leicester from second tier underachievers into top-flight mainstays, O'Neill enjoyed a golden period in Glasgow which included seven major trophies, including three league titles, during his five years in charge.

He led Celtic to their first domestic treble since 1968 in his maiden season and followed that success by taking them to the UEFA Cup final -- their first European final since 1970.

The long-awaited arrival of Rangers back in the Scottish Premiership next season would give O'Neill a tasty challenge to sink his teeth into and he would surely be warmly received either at Parkhead, the City Ground or Villa Park if he accepted the role of the returning prodigal son.

But for now, O'Neill is determined to ignore the debate about his future as he focuses on Ireland's first major tournament since he took over in 2013.

Just 12 months ago, he was widely criticised after a lacklustre 1-1 draw against Scotland in Dublin that left Ireland's Euro bid in the balance following their failure to reach the 2014 World Cup.

Yet he silenced the critics by masterminding a 1-0 victory over world champions Germany that helped secure the play-off tie that ended in a hard-fought 3-1 aggregate success against Bosnia.

A daunting draw has pitted Ireland against Belgium, Italy and Sweden in the finals, but success in those glamour fixtures would make O'Neill an even more alluring object for his admirers' affections.