In the video, Mr Tai-Rakena told a woman: "You're not coming in here girl, you're too intoxicated. Away you go."
The woman responded: "I maybe have drunken four, five beers but guess what? My friends don't deserve to be treated like that."
The man disputed the doorman's contention he was too drunk.
The doorman claimed the female ministry employee also threatened to tell local gangsters about the incident.
Mr Tai-Rakena repeatedly told the pair "good night" and "away you go".
Bar owner Tom Condon told NZME News Service the behaviour caught on camera was too common nowadays.
"The doorman watched a group of them walk down the road. He picked two of them he wanted to talk to a little bit more. He said, 'Mate, look, I think you might be too intoxicated to come in, I need you to walk a straight line.' And he refused."
Mr Condon said two women previously allowed in the bar then came out and "started abusing" Mr Tai-Rakena.
He said Mr Tai-Rakena was abused for about 13 minutes before he started filming the pair.
Mr Condon said another woman who was with the group ducked for cover when Mr Tai-Rakena started recording.
The bar owner said he'd not heard from the individuals involved but an MSD regional manager visited today and apologised.
Mr Condon said it would be unfair to his staff to let the workers back into the bar.
However, he also said everybody "makes mistakes" and he could forgive the abusive group if they apologised.
Mr Condon said it was bizarre the man claimed he and his companion were being denied service or entry because they were "white" when the man's companion was Maori.
He said people frequently abused his staff - in a separate case, a man refused entry then lurked in the neighbourhood yelling "general abuse" at staff for two hours.
Mr Condon said it was rarely worthwhile calling police about such incidents, as police were busy dealing with other problems.
MSD confirmed it had stood down two staff members and was carrying out a "full investigation" into a "verbal confrontation" between Work and Income employees and bar staff.
"Work and Income will not tolerate poor behaviour or racist language, and we are taking this matter very seriously," the ministry said in a statement.
The ministry said it had since met various parties involved, including the bar staff.
"Two staff members have been stood down while the investigation continues. In the interests of a fair process, this investigation needs to be completed before we can comment further."