The 72-year-old has turned Bayern’s fortunes around, from trailing in the Bundesliga by five points when he took over in October, to their current 16-point lead.
However, Heynckes has insisted he will leave in May and answered with irritation when asked about attempts by Bayern’s chiefs to entice him to stay.
“There is nothing more to say about that – it’s a labour of love, which is in vain,” he said tersely ahead of Saturday’s German league game at Mainz.
“We should put the issue to one side and concentrate on the football.”
This is Heynckes fourth stint as Bayern head coach.
He enjoys legendary status in Munich having steered the club to the 2013 treble of Champions League, Bundesliga and German Cup titles.
The efforts of Bayern president Uli Hoeness and chairman Karl-Heinz Rummenigge seem to have fallen on deaf ears despite regular meetings with Heynckes.
Hoeness stirred up the issue earlier in the week.
Having initially said there is “no plan B” in the search for a new head coach, Hoeness now puts the chances of Heynckes staying on at just “10 percent”.
Bayern’s president is used to getting his way, but Heynckes just wants to focus on Bayern’s streak of 18 wins in their last 19 games in all competitions.
“Regardless of things turn out, I will continue to work hard and I hope we can continue on the road to success,” said Heynckes.
Bayern start a run of three games in eight days as they play Mainz away, then visit third-division Paderborn in the quarter-finals of the German Cup on Tuesday.
Then comes a plum Bundesliga match when they host third-placed Schalke at the Allianz Arena a week on Saturday.
Bayern stars Manuel Neuer and Thiago Alcantara are close to making their comebacks from injury.
Defender Mats Hummels is back after illness, but Arturo Vidal is set to sit out the Mainz match with gastroenteritis.
Back-up striker Sandro Wagner is available despite turning an ankle in training, but left-back David Alaba is struggling with a groin injury.
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