Workers from the Shropshire and Mid Wales branch of the Communication Workers Union (CWC) were out on pickets across the region on Thursday as they took industrial action in a dispute over pay and conditions.
The action was continuing today, with another 48-hour walkout planned for Wednesday and Thursday next week if there is no agreement between the CWC and Royal Mail bosses.
Pickets were taking place at Wellington, Shrewsbury, Oswestry, Oakengates, Tweedale, Market Drayton, Whitchurch, Parcel Force in Atcham, Ludlow, Newtown, Welshpool, Llandrindod Wells, Machynlleth and Aberystwyth.
Ruth Meadows, secretary of the Shropshire and Mid Wales Branch of the CWU, said that workers were committed to the action, and were still seeing strong support from the public.
She said: "We had good support on the picket lines, lots of people beeping their horns.
"People are still shouting 'good luck' and so such. A lot of people are either affected or they know someone who is affected."
She added: "The university workers have been on strike today, the rail workers are still going out, it is not just us, it is across the country."
Communication Workers Union (CWU) general secretary Dave Ward, meanwhile, has called for Royal Mail CEO Simon Thomson to be sacked.
He said: "Negotiations have been difficult because the CEO chooses moments when he comes into the talks.
"He spends most of his time telling shareholders that the company's got a good future and he also spends most of the rest of his time talking to our members directly on social media, goading them into feeling bad about the situation, intimidating them almost on a daily basis.
"There's no CEO in the world that would operate on the basis of the way that the CEO of Royal Mail and the board are operating at the moment.
"The members have voted overwhelmingly for no confidence in the CEO and the board, they should be sacked for what they're doing to one of the greatest companies in the UK, they should be sacked."
Mr Thompson has said "negotiations involve give and take" but the Communication Workers Union's approach was "just take".