House prices in Caerphilly County Borough dropped by 3.4% in February, despite witnessing a 3.1% rise over the last 12 months.
It comes as annual price growth across the UK fell to its lowest level in six years.
The latest data from the Office of National Statistics shows that the average property in the area sold for £132,469 – significantly lower than the UK average of £226,234.
Across Wales, property prices have risen by 4.1% in the last year, to £159,559. The region outperformed the UK as a whole, which saw the average property value increase by 0.6%.
The data comes from the House Price Index, which the ONS compiles using house sale information from the Land Registry, and the equivalent bodies in Scotland and Northern Ireland.
The average homeowner in Caerphilly will have seen their property jump in value by around £22,000 in the last five years.
The figures also showed that buyers who made their first step onto the property ladder in Caerphilly in February spent an average of £119,199 – around £19,000 more than it would have cost them five years ago.