All six were banned for alcohol-related disorder following a recent meeting of the town's Pubwatch committee.
The bans range from 12 months to five years, with two others given warning letters.
Newtown Police Sergeant Stephen Vaughan said: “Behave or be Banned is an effective tool to help prevent, reduce and tackle alcohol related offences within our communities.
"In addition, those who are found in possession of illegal controlled drugs on licensed premises can also be taken forward for discussion with a view to being banned.
"This ban prevents all those listed from entering any licensed premises in Newtown and the surrounding area.
“Licensees will not tolerate anti-social behaviour in their premises and BOBB keeps such people out, making it safer and more enjoyable for everyone else.
“During this meeting we agreed any behaviour where violence is threatened or used against police officers, door staff or licensees will result in an automatic 12 month minimum ban."
He said the five year ban was handed out for an assault on two police officers.
“The message is simple – Behave or Be Banned!”