Surendra Patel, state minister for public works department (PWD), on Monday evening slapped the party worker in full public view.
The incident happened at a party meeting in Varanasi while the minister was listening to problems being raised by supporters.
When confronted by the worker on the high-handedness and hooliganism of some of the party members, the minister lunged towards him.
He first tried to gag him and then slapped him, following it up with a punch.
Patel, who is the junior minister and a close associate of PWD minister Shivpal Singh Yadav, warned the worker, following which he apologised with folded hands.
It was caught on television cameras.
Bharatiya Janata Party (BJP) spokesman Vijay Bahadur Pathak criticized the minister, saying that the arrogance of the minister with his own workers and supporters was reflective of the malice in the Akhilesh Yadav government.
"When the minister can beat up his own supporters like this, just think of what he must be doing to common people who go to petition him," Pathak said.
This is not the first time that Surendra Patel has lost his cool.
The minister also beat up some people on Dec 29 last year during a blanket distribution function organised by the party.
Members of the state government and party workers have been courting controversies ever since the formation of the SP government March 2012.
Only recently UP minister Gayatri Prasad Prajapati saw nothing wrong in his party workers bashing up toll plaza staffers.
"There is nothing wrong in case the toll staff has been given just four-five slaps," he told reporters, accusing the media of unnecessarily going on an overkill on the issue.
Chief minister Akhilesh Yadav and Samajwadi party chief Mulayam Singh Yadav have many times in the past warned party workers not to indulge in hooliganism or face action. However, neither party workers nor ministers seem to be heeding the two leaders.