Over half feared that the scheme could become permanent, while 51% supported the involvement of private sector insurance to facilitate an orderly exit.
Angel Mas, president of Mortgage Insurance Europe at Genworth, said: “With an eye to the near future, it’s clear that the government should start thinking about the exit strategy for the scheme now.
“Just turning off the high loan to value mortgage finance tap at the end of 2016 will risk a cliff since the issues that led to the introduction of Help to Buy 1 and 2 have not gone away.”
Eight of 10 Conservative MPs were optimistic that the scheme could increase house building, whereas only one in four Labour MPs felt the same.
Over half of Conservative MPs felt house prices are likely to increase due to help to buy, while eight out of 10 Labour MPs agreed.
Mas added: “There is optimism that the scheme will facilitate house building, but as Morgan Stanley has already indicated, house builders make investment decisions 12 to 18 months in advance, which requires a clear picture of what will happen to high loan to value mortgage lending after 2016.
“We believe that private involvement should be gradual and phased in through the life of the current government scheme.”
72% of MPs were concerned about the impact on the taxpayer if the government guarantee was significantly called upon.