Kevin Gilliland, network and sales director at the Post Office, said the Communication Workers Union's (CWU) decision to strike will "cause disruption to customers."
The CWU are calling for an above-inflation pay agreement when last year our overall performance was a loss of £116 million.
We must reverse this loss of public money. Strike action can only cost our people money, cause disruption to customers and threaten our plans to turn the business around and keep our branches on high streets and in city centres across the UK.
The CWU's call for its members to stop proactively introducing financial services to customers is extremely irresponsible.
More top news
His death sparked tributes online and #BeMoreMartyn trended - now a play is celebrating the life of Manchester attack victim Martyn Hett.
Many affected were seen burying their faces in their hands and people flooded from the room in tears.
June Tron's son Philip was one of 22 people killed when suicide bomber Salman Abedi detonated his device.