The Saint John and District Labour Council wants business owners to pull advertising from three of the city's private radio stations.
It's hosting information pickets outside some local businesses.
Local advertisements are being run on Big John FM, CFBC and K-100, where seven employees have been on strike since June after eight months of negotiation failed to lead to a first contract with Halifax-based Maritime Broadcasting System.
"We're asking businesses in the Saint John area to not advertise on striking radio stations at this time, trying to make it a level playing field," said Ron Oldfield, president of the labour council.
"The employees have given up their wages. We would expect the employer to give up their profits at this time, until both parties can get back to the bargaining table."
The biggest complaint in the contract dispute is mandatory unpaid overtime and low salaries — which are close to minimum wage, unionized staff claim.
The union says employees at the three private radio stations have gone 12 years without an across-the-board wage increase.
A company spokesperson has said the station's offer of a wage increase is "realistic and fair."
A representative for the striking workers says there has been no progress since talks broke down in June.