The index found that house price growth remains stable across most of the UK, although prices in London are increasing faster than the UK average.
The year on year increase reflected growth of 3.1% in England, 0.8% in Scotland, 0.6% in Wales and 1.9% in Northern Ireland.
Andy Knee, chief executive of LMS, said: “This morning’s figures illustrate an increase in house prices in all regions of the UK, with Northern Ireland experiencing its first growth year-on-year since February 2008.
“The primary issue for those looking to buy their first home is sourcing a deposit and as house prices continue to rise this chasm between buyers and renters is widening, many are resigning themselves to ‘forever rent’.”
The Index revealed average mix-adjusted house prices in May 2013 stood at £248,000 in England, £157,000 in Wales, £134,000 in Northern Ireland and £180,000 in Scotland.
In May London continued to be the English region with the highest average house price at £416,000.
The North East had the lowest average house price at £144,000. London, the South East and the East of England all had prices higher than the UK average price of £239,000.
Ben Thompson, MD at the Legal & General Mortgage Club, said: “Once again the ONS data suggests that UK house prices are continuing to rise this month.
“It’s always great to see positive data concerning the housing market. All signs are that the recovery is gathering significant momentum.
“However it is important that we remember it’s still early days and although the picture looks rather rosy in certain areas, such as London, recovery is a slower process in other parts of the country.”
The ONS said that figures found that when London and the South East are excluded house prices increased by just 1.9%.
Thompson added: “The importance of government stimulus cannot be underestimated and the confidence it has created and has been very welcome.
“Attention must now be turned to tackling the long-term structural issue of inadequate housing supply in the UK.
“Equally the industry must start to think about how we will be able to continue this good start and ultimately stand on our own two feet once stimulus is removed.”
