Welsh practices outstripped England this year in quality achievement, the final UK quality data for 2007/8 show.
The announcement will fuel growing resentment among GPs in Wales that they earn consistently less than their counterparts in England.
The data show that the average Welsh practice earned 973 points, against England's 968. The country's 490 practices pushed their average quality framework achievement up by 25 points from 2006/7, almost double the increase in England.
Wales averages 14 per cent higher prevalence than England, but similar list sizes mean practices have to work harder for the same level of quality pay.
Latest earnings figures show that the income of Wales' 1,773 contractor GPs dropped 4.3 per cent to an average of £97,772 in 2006/7. In England, average income for the same period dropped 1.8 per cent to £111,566.
'If you come to Wales as a GP, you will work harder, take home less money and will have a smaller NHS pension,' GPC Wales negotiator and Morgannwg LMC secretary Dr Ian Millington said.
'That's what it costs to be a GP in Wales and it is time that the Welsh Assembly government addressed this as a matter of urgency,' he said.
Monmouthshire remained Wales' highest-scoring local health board (LHB), with an average of 990 points, while Merthyr LHB scored lowest, with an average of 942 points.
Eighty-five per cent of practices received more than 950 points, up from 68 per cent in 2006/7. Only six practices achieved fewer than 800 points.
'This is a fine performance from Welsh GPs,' said GPC Wales chairman Dr David Bailey. 'Especially as overall prevalence in Wales is 14 per cent higher than in England.'
Although lower average list sizes in Scotland and Northern Ireland mean practices do not lose out on quality pay, pay is still lower. In Scotland, contractor GPs earn £89,468, and in Northern Ireland £93,316.
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