The public sector in the Westcountry paid out more than £1 million last year for the work of dozens of trade union staff.
Research by the TaxPayers' Alliance, which campaigns for lower taxes and better government, revealed there were the equivalent of 44 full-time union staff members paid for by local councils, the NHS, police and fire services in Devon and Cornwall.
The cost totalled £1.22 million – part of a national £113 million bill paid out of the public purse, for more than 3,000 union staff.
The TaxPayers' Alliance said the money amounted to union "subsidies" and that Government reform of the civil service "must go further to include all of the public sector rather than just Whitehall and its quangos".
Matthew Sinclair, chief executive of the alliance, said: "It is simply wrong that taxpayers are seeing their money used to pay thousands of trade union activists who organise strikes which disrupt the services they rely on and pay for handsomely.
"Thousands of staff who should be working for public services are working for the trade unions instead.
"Managers at too many public sector organisations are completely failing in their responsibility to control these costs and even keep proper records of the subsidies they are providing to the trade unions.
"Tens of millions of pounds are being wasted and supporting aggressive political campaigns.
"The Government needs at least to extend the proposed reforms to the entire public sector and cut this scandalous subsidy."
The highest costs locally, according to the report, were at the region's largest authorities.
Devon County Council spent £237,869 and Cornwall Council £173,120, both for the equivalent of six full-time union posts. The national organisation with the highest number of staff working for trade unions was the Department for Work and Pensions with 272 full-time equivalent staff.
Unions dismissed the report as "nonsense".
Nigel Costley, secretary of the South West TUC, said it typified the "class war" peddled by the alliance. He added that union representatives helped solve problems, saving employers time and money, made workplaces safer and had a "positive" effect on businesses.
Mr Costley said: "Independent and impartial studies show just the opposite of these figures.
"If you don't have the solution in the workplace the only other place is in the courts which costs employers massive amounts of money, especially when they have got things wrong."
Without union representatives, he added, staff would have "no voice" over crucial issues such as pay, terms and conditions and safety.