We think they've undermined the bargaining process by telling us they have no money while giving bonuses and a pay rise to non-union workers."
Gallagher says the strike action will involve 25 to 30 staff, which is approximately a third of the overall headcount at the company.
Keith Ikin, Māori Television chief executive, said the offer of a base pay rise and a payment based on individual performance made during recent mediation and talks is consistent across the organisation.
"We believe that Māori Television has been proactive in engaging with the union, and the offer put forward at recent talks is both fair and reasonable and supports the organisation's performance-based remuneration approach," Ikin said.
"We are disappointed to learn of potentiation of strike action on August 8 via the media. A contingency plan has been put in place to ensure that viewers are not impacted by the action and that they can continue to enjoy our programmes.
"We remain committed to progressing the deal and reaching an agreement in the interest of providing certainty for the 27 affected Māori Television staff in the union collective."
Gallagher added that Māori TV was not living up to its claims of being a values-based organisation.
"The direction and behaviour of the management at Māori TV is seriously lacking for a company and organisation which promotes the values of tikanga."
The strike action will run for 24 hours on 8 August.