Stoke have made a disappointing start to the new Premier League season, losing four of their five matches to date to sit bottom of the table on one point.
Barton played under Hughes at Queens Park Rangers and the controversial midfielder has blasted the Welshman's managerial capabilities and claimed that the head coach has 'really, really poor people skills'.
"Mark Hughes is a terrible manager. Stoke are bottom of the league. I thought his people skills were really, really poor," Barton told the Daily Mail.
Barton is currently serving a three-week Rangers suspension following a training-ground incident with teammate Andy Halliday last week, while the 34-year-old is also the subject of an investigation for allegedly breaching betting rules.