Civil servants could see "basic workers rights" slashed, including holidays, sick pay and child care, and even their jobs put at risk, with managers urged to look at scaling back costs, a union claimed on Wednesday night.
The Public and Commercial Services union's general secretary Mark Serwotka said: "It is impossible to separate this from the Government's wider political project to unpick the welfare state and drive down pay, conditions and employment rights across the economy, and we are determined to oppose it at every step."
The union has seen document sent to all departmental directors of human resources made it clear that all terms, conditions, policies and agreements are to be looked at, including working hours, annual leave, sick pay, and family-friendly arrangements such as childcare, flexitime, part-time and term-time working, and job sharing.
Serwotka said: "Amid an imposed pay freeze, and cuts to pensions and redundancy terms, the Cabinet Office now wants to undermine some very basic working conditions that any decent employer should offer.
"Taken together, it means civil servants face having their terms and conditions ripped up while access to union representation is being significantly undermined."
The Guardian reported that the cuts would target 450,000 public employees, according to a leaked letter sent to every human resources director across the civil service.
Plans for cost-cutting are expected to be in place by the end of the year. Benefits and schemes under review will include family-friendly scheme of flexitime, travel and expenses, disciplinary procedures and performance management.
The aim is to deliver all reforms over two years, starting in April 2013.
A Cabinet Office spokesperson told the Guardian that the civil service was being reformed to make it faster, more unified, focused on outcomes not process, and ultimately more enjoyable to work for: "Because we want to attract the best staff, we will remain an employer with good terms and conditions, as we have always been.
"However, while there has been significant recent change in pay and pensions, there are other terms and conditions that have not been updated and are now outliers compared to best practice. We will address this and ensure a modern employment offer is available to all."