In December, the housebuilder completion deadline had been extended by a month to 31 January, with housebuilders previously required to reach practical competition by 31 December.

The legal completion deadline still remains the 31 March, with borrowers expected to have the keys to their home by 6pm on that date.

A Department for Levelling Up, Housing and Communities spokesperson said: “Supporting aspiring homeowners is a government priority. We have extended the Help to Buy deadline to 17 March to make sure people do not lose out on their homes because developers haven’t met the building deadline.

“Housebuilders must make sure they finish all building work by this date and the legal completion deadline remains 31 March.”

Buyers must check with builders

The government said that those using Help to Buy should check with their homebuilders that they can meet the dates.

If a developer cannot meet the deadlines they have to let the customer know and return the homebuyer’s reservation fee in full, release them from a contract if exchanged and return the full deposit.

No plans to extend Help to Buy

Help to Buy closed for new applications on 31 October and Housing minister Lucy Frazer said earlier this month that there was no plan to extend or replace the Help to Buy scheme after its ends on 31 March.

She pointed to other schemes such as First Homes and the mortgage guarantee scheme, the latter of which was extended by a year.

Related: End of Help to Buy: 10 alternatives for first-time buyers