The number of new build sales across Britain has fallen by 35% year-on-year from 124,009 to 79,997, according to HouseScan.
The South West has seen the largest decline in new build sales, with total transactions down 40% on the previous year.
This was followed by the North East and London, which declined by 39% year-on-year.
However, while all British regions noted a decline, smaller areas saw numbers rise.
In West Devon, there were 124 new build transactions over the last 12 months, a 343% increase on the 28 new homes sold over the previous 12 months.
Merthyr Tydfil and North Ayshire have also seen some of the largest increases in new build transactions, up 188% and 137% respectively.
Harry Yates, founder and managing director of HouseScan, said: “It’s clear that when analysing transactional performance across the new build sector, the issues posed by COVID-19 have had a detrimental impact.
“This has primarily been due to the restrictions placed in the initial months of 2020 preventing many in the sector from both building and selling units.
“However, as with the regular market, the new build sector has enjoyed a boost in activity following the market’s reopening and the dangling carrot of a stamp duty saving.
“Of course, this initial demand will take time to appear at a top-line transactional level, but it places the sector in a strong position for a positive year ahead.
“While demand across the regular market may see a decline come March and the end of the stamp duty holiday, we expect to see the new build sector remain favourable amongst UK buyers and, as a result, both transactions and price growth should continue to climb in 2021