The value of semis rose by 5.6% over the year, the Land Registry figures show, ahead of flats (up 5.4%) and detached homes (up 5.1%).
Overall, property prices increased by 5.1% over the year and by 0.9% from March to April.
The average home was valued at Â£179,817, the Land Registry said.
Prices rose the fastest in London over the year, up 10.9%, and in the South East of England, up 8.8%.
The slowest annual property price growth was in Wales, up 0.3%. Prices in Wales fell by 1.1% in April compared with March.
The pace of property price rises generally has slowed, although the picture features significant regional differences.
"The property market in Wales and the North East [of England] is a million miles away from the south-east corner of England," said Jonathan Samuels, chief executive of Dragonfly Property Finance.
"The broader fall in the number of property transactions over the last year suggests a natural slowdown in the property market after a period of exuberance."
The figures come as insurer Legal and General said there was a need for purpose-built homes for the older generation.
Nigel Wilson, chief executive of L&G, said that there were more than five million under-occupied homes owned by the over 55s.
Two-thirds of them were looking to downsize but there were no appropriate homes for them, he said.
The price of semi-detached homes rose at the fastest rate of any property type in England and Wales in the year to the end of April, data shows.