Guardiola, who won more than a dozen titles in his four years at Barcelona, joined the Bavarians in July 2013, winning dominant back-to-back Bundesliga titles in his first two season in charge.
Undefeated Bayern are already seven points clear at the top of the league after a record-breaking nine-match winning start as they chase an unprecedented fourth consecutive Bundesliga crown and the third under Guardiola.
"I have said that in the second half of 2015 there will be a (contract) discussion and after that there will be clarity," Rummenigge told reporters ahead of his departure for London where Bayern face Arsenal in Tuesday's Champions League group match. The team had left a day earlier.
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"That talk is still pending but it will still take place sometime before the end of the year," he added.
"There are a lot of things in favour of Bayern but it is clear there are most likely other good-looking brides out there other that Bayern. But at the end of the day we are optimistic that Pep Guardiola will stay at Bayern."
Bayern are top their Champions League group with two wins in two matches but the Spaniard has yet to emulate predecessor Jupp Heynckes who won the treble, including the Champions League in 2013.
Guardiola, who has refused to comment on any issue related to a new deal with Bayern, is reportedly top of the wish list for several major European clubs.
"I know of no interest for Pep Guardiola but I am also not interested in that. We have a season to play and am optimistic he will be our coach after July 1, 2016."
(Reporting by Karolos Grohmann; Editing by John O'Brien)
