The scheme, launched by Chancellor George Osborne, has the capability to support £130bn of lending over its three year lifespan – equivalent to £43.33bn a year.

However, analysis from Genworth suggests Help to Buy supported £5.76bn of mortgage lending in 2014, which amounts to 13% of its potential.

Boosting the scheme could be equivalent to an extra 200,000 first-time buyers.

Simon Crone, vice president for mortgage insurance at Genworth, said there were first-time buyers who were not benefitting from the scheme.

“At a time when hopeful first-time buyers face multiple challenges to reach their goal of home- ownership, it seems unacceptable that Help to Buy is not maximising its capabilities to help more achieve this aim,” he said.

“Given low rates of house building, it is perhaps a blessing that the market has not been flooded by an extra 200,000 first-time buyers overnight.”

He said further action from government and others in the sector was necessary:  “But if careful steps are taken and it is paired with greater house building to guard against house price inflation, our analysis shows that Help to Buy could help restore the first-time buyer market to its former glory.”

With the scheme due to expire in 18 months’ time, Crone said lenders offering mortgages to first-time buyers needed further support.

“It leaves a big question mark over how access to high loan-to-value loans would survive in a climate of tighter lending restrictions when Help to Buy is withdrawn in a little over 18 months’ time. There is little in the data to inspire confidence that 95% loan-to-value mortgages can survive and prosper without some form of support in place.”