Unions have hit back at Post Office managers who claimed that Saturday was "business as usual" despite industrial action.
Members of the Communication Workers Union (CWU) and Unite staged a 24-hour walkout in protest at job losses, franchising of Crown offices and the closure of a final salary pension scheme.
Workers mounted picket lines outside hundreds of Post Office branches but managers insisted it was "business as usual" in all but a handful of branches in its 11,600 strong network.
Kevin Gilliland, Post Office network and sales director, said: "We want to reassure people that over 99% of our network is operating its usual Saturday schedule today.
"Of the 279 branches where action was called, 190 are open for business, in addition to many thousands more around the country."
He added: "We want the unions to join us in talks to discuss our strategy and find a constructive way forward. Their members work very hard to give our customers the best possible service in the run up to Christmas, and this action can only cause concern."
CWU General Secretary Dave Ward said the Post Office is at "crisis point".
"It needs a new strategy as a matter of urgency. No-one is thinking of the future," he said.
"This isn't good for workers, it isn't good for customers and it isn't good for the future of the business. The CWU will not simply stand by and see another British Industry destroyed.
"We have a simple demand - that the government pauses the cuts and brings stakeholders together for a structured period of talks to develop a plan that is about more than managing the decline of the service - our members and the public deserve nothing less."