A mass meeting of postal workers and union officials was set to be held outside the Weston-Super-Mare mail centre on Thursday 29 August.
They were to decide on the next stage of action.
The dispute centres on allegations of bullying, large workloads and the breaking of health and safety rules by management.
Some 130 workers in Weston-Super-Mare struck two weeks ago with workers in nearby Bridgwater.
It was the first time postal workers there had been on strike in the town for 20 years.
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