Prices in April were up just 0.9 per cent compared to the same month a year earlier, the numbers showed.
The rate is well below the official level of consumer price index inflation, which was recorded at 2.8 per cent for March.
And compared to the previous month, average house prices in April actually fell, dipping by 0.1 per cent.
Yet the figures mask sharp differences between various parts of the UK, explained Jonathan Samuels, CEO of Dragonfly Property Finance.
“In reality, the market remains fragmented, with prices in London rising at a rate of knots and many areas in northern England still seeing declines,” Samuels said.
“In some regions, the market feels undercooked, in others, not least the capital, it feels overcooked.”
Levelled out, the average UK home is worth £165,586, Nationwide said.
The survey added that there are signs that government efforts to stimulate credit, such as the funding for lending scheme (FLS), may be boosting activity in the housing market.
“Mortgage approvals for house purchases averaged just over 53,000 per month in the first quarter of 2013, up from an average of 51,000 per month in 2012,” the report said.
Nationwide chief economist Robert Gardner added to the bullish tone: “There are reasons for optimism that activity levels will continue to strengthen in the months ahead,” he commented.