Between March and April, prices rose by 1% and the annual pace of growth rose to 5.2%.
The average house price is now £193,048 – the highest figure yet re corded by Nationwide.
Jonathan Hopper, managing director of Garrington Property Finders, said: "House price growth before the May Election is somewhat of a surprise.
"However, demand was always there even though the property market had come off the boil over the past six to nine months.
"Fundamentals supporting the market are very strong right now. Mortgage rates are obscenely low, and may go even lower, inflation is at zero and the jobs market and economy are strengthening.
"People feeling better off and actually being better off can only boost the property market."
Jonathan Samuels, chief executive of Dragonfly Property Finance, added: "The 1% April price increase, coming a little out of the blue, underlines the inherent volatility of the property market. It truly is a law unto itself.
"Does a strong economy and subdued pace of activity really constitute an anomaly? On paper it might, but in practice the property market is rarely that simple.
"While mortgages are cheap, employment high and the cost of living low, people are far more cautious than they were in the past.
"There is an element of caution, and conservatism, in the market that perhaps wasn’t there before 2008.
"The fact that first quarter economic growth wasn’t as strong as expected is certainly consistent with more subdued activity levels.
"People are more aware than ever that the property market is a double-edged sword. And prices overall are high. Buying a property is not a decision that can be taken lightly.
"We would expect activity levels to pick up after the General Election, particularly at the higher end of the market, but 2015 as a whole is shaping up to be a middling year for the market. But is this necessarily a bad thing?"