The "eye-watering" costs are hitting the poorest and most vulnerable hard because they rely disproportionately on pay-as-you-go mobiles, which incur the highest charges, it was claimed.
A National Audit Office investigation found that despite attempts to limit them, high cost numbers, which start 084, continue to be used "extensively" across Whitehall.
Around one third of central Government helplines are charged at the higher rate but account for 63% of the calls made to Government.
Despite the increased costs, which can be split between the provider and the organisation using them, the service is no better, according to the NAO.
Margaret Hodge, who chairs the Public Accounts Committee, said: "It is not acceptable that vulnerable people are facing some of the highest charges to call central Government about important issues such as benefits and redundancy.
Average landline call costs to standard geographic numbers and those that begin 03 work out at around 3.4p per minute and 1.1p from mobile phones, which often usually offer free minutes in package deals, according to latest Ofcom research used by the NAO. That rises to 5.6p from landlines for 0844 numbers and 17.1p from a mobile. Freephone numbers are anything but for mobile users, with the average charge per minute for using an 080 prefix 16.2p.
Although Cabinet Office guidance states it is inappropriate to use the costly phone services when dealing with vulnerable people or those on low incomes the NAO found at least 59 cases where the phone lines were predominantly dealing with those groups. It pointed to research by Citizens Advice that found 61% of clients had been put off from calling Government telephone numbers because of fears about the cost.
NAO head Amyas Morse said: "Callers do not receive a better service from higher rate numbers and many callers are put off calling Government phone numbers altogether. The most vulnerable callers, such as low-income households, face some of the highest charges."