The design that gets the most support from the first referendum will go forward to a second referendum early next year.
Voters would then have a simple choice between the new design and the existing flag.
"We do the workshop and the hui to inform people as to what the process is and we are really keen to hear people's views on the process," Mr Mulholland said.
He said the Southland hui had a strong turnout.
"People are quite intrigued by the history because people feel like they need to know the background of the flag to make an informed decision.
"It has a particular history for Maori that our people need to be aware of as well, as our flag did come about from the New Zealand war period.
"Our role is to come up with the four alternatives that people will vote on. This is about the public having the decision and everyone gets a vote."
On Tuesday, there will also be an information stand in the City Focus - which will move into the library if it rains - from 10am to 3pm, as well as a public workshop from 5.30pm to 7pm at the Millennium Hotel.
-Find out more at www.flag.govt.nz or www.standfor.co.nz.