Only one win in their last 11 league games has sent the Welsh club down to 15th in the table after they had climbed to fourth by beating Manchester United early in the season.
"We all feel at the club that something needs to change to get things back on a positive note as quickly as possible," Jenkins, who was speaking at Windsor Castle after receiving an OBE for services to sport in Wales, told the BBC on Tuesday.
"The difference between the end of August and how we find ourselves today is something we haven't experienced at Swansea before, such a big change around from where we were after beating Man United in the last game in August," he added.
"It just again highlights if things are not dealt with and addressed early enough the Premier League is very unforgiving, and unless every angle and everybody's focus is 100 percent week in, week out, things can change very quickly."
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Monk guided Swansea to an eighth-place finish last season, their highest top-flight league finish.
(Reporting by Shravanth Vijayakumar in Bengaluru, editing by Ed Osmond)
