The Post Office is committed to sustaining its 11,600-strong branch network, saying its modernisation plans have added 200,000 extra opening hours in recent years.
Thousands of branches have been "transformed", with 4,000 open seven days a week, leading to shorter queues as people use Post Offices outside office hours, said the organisation.
Tom Moran, general manager of the Post Office network, said: "Our branch network of 11,600 branches is bigger than all the banks and building societies combined.
"The extra opening hours we've added over the last four years add up to the equivalent of 5,000 new branches - that's a significant achievement that makes a real difference for our customers.
"More and more people have a local Post Office open early in the morning, late at night, and on the weekend.
"This sends out the clear message that we are committed to sustaining our branch network at its current size of more than 11,600 Post Offices, and to improving it so we can meet the ever-changing needs of today's customers."
:: The Communication Workers Union said earlier this month that its members in Post Offices had voted in favour of strikes in a dispute over job losses, pensions and the franchising of Crown offices.
Labour leader Jeremy Corbyn said: "The never-ending cycle of cuts, closures and franchises is destroying a much-loved British institution. It is vital that the Government now urgently intervenes and works with key stakeholders to put together a strategy for the future of the Post Office, in order to protect this publicly-owned service from withering away."