Union leaders are furious at UK government plans to pay court workers in Wales and the north of England less than their counterparts in the south.
Workers in magistrates, crown and county courts could be affected
The plans for a new regional pay system by the Department for Constitutional Affairs (DCA) would apply to workers in crown, county and magistrates' courts.
The Public and Commercial Services Union (PCS) said the plans would lead to a north-south divide among staff.
The DCA said regional pay reflected the reality of the job market in the UK.
The vast majority of court service workers in Wales, and those in England north of Kings Lynn, would be put into the lowest of five proposed pay bands, according to the PCS, which represents court staff.
The union said the starting salary for the majority would be around £11,700, compared with £14,400 for employees in other parts of the country.
Jeff Evans, the PSC's senior national officer for Wales said the public sector was a major employer in the country.
Any pay detriment could have a direct impact on the Welsh economy, he warned.
He said: "Wages in Wales are, on average, 13% lower that the UK average."
"It follows that any reliance on market forces to determine regional public sector pay rates would inevitably disadvantage Welsh workers.
"Moreover, the imposition of regional pay could seriously hamper National Assembly efforts to reduce the prosperity gap between Wales and the rest of the UK, " he added.
Mark Serwotka, the union's general Secretary, called on ministers to intervene.
"These proposals are not only scandalously unfair but will entrench the North-South divide by driving down pay in some of the most deprived areas in the country.
"Civil service pay is already riddled with inequality and the fear is that with government departments seeking to drive down wages, these proposals represent the thin end of the wedge."
But a spokesman for the DCA said there was nothing new in regional pay and the department already paid a premium for people working in certain parts of country.
He said: "DCA's driving principles are to offer fair pay to people based on the job they do, where they do it and how well they perform.
"Regional pay reflects the reality of the job market in this country.
"If we want to attract and retain the people with the skills we need, where we need them - especially in London but also in other big cities like Manchester - we have to reward them properly."