Councils and public bodies in England are poised to be handed powers to enable them to buy greenbelt land without overpaying as part of the government’s drive to build 1.5m homes by 2030.

Greenbelt landowners who are unwilling to sell would face compulsory purchase orders (CPOs) that would force them to hand over their land if the site could host a “quality housing scheme” in the public interest.

Under the proposed rules, which are being consulted on, these landowners could be forced to sell at a capped benchmark value that the government has said will provide “fair but not excessive return” for the landowner, as well as “maximising community benefits”.

The proposals come two weeks after the deputy prime minister, Angela Rayner, set out wide-reaching planning and housing policy reforms aimed at accelerating housebuilding.

These included the introduction of new mandatory housing targets for councils, under which authorities would have to identify enough land in their local plans to meet housing need.

In some areas this would result in significant increases in the number of new homes required, such as the north-west of England, whose target rose from 21,500 to just under 38,000 homes, and the east of England, where the target rose from 35,000 to nearly 45,000.

The changes also included a call for councils to review greenbelt areas for development if needed to meet housing targets. The government said it wanted to take a “more strategic approach to [greenbelt] land designation”.

The green belt was introduced nationwide in 1947 under the Town and Country Planning Act to prevent urban sprawl and protect areas on the edge of towns and cities from development. It covers 6,300 sq miles, about 13% of England’s area.

Much of the green belt is owned by farmers, with about 65% of all the country’s greenbelt used for agriculture. However, there are some investors who have been prospectively buying up greenbelt land in recent years in the hope that planning rules are loosened.

There are fears that landowners who were holding greenbelt land that had no development value before the changes could now attempt to cash in.

To address this, ministers are putting forward changes to compensation rules, first reported by the Times, which will “remove inflated values of land based on the prospect of planning permission” and ensure schemes that are in the public interest can progress.

If a price cannot be agreed, the government is considering giving powers to allow local authorities and Homes England, the government’s housing delivery agency, to “take a proactive role in the assembly of the land supported where necessary by compulsory purchase powers”.

The prime minister’s spokesperson confirmed that the government was consulting on plans to cap the amount landowners could receive, and said it would provide more details after the consultation closes.

Some planning and housing experts have said Labour will only be able to hit its goal of building 1.5m homes by 2030 if more homes are built on greenbelt land.

The government has conceded that building on brownfield land – areas that were previously developed but have fallen into disuse – will not solve the housing crisis on its own, and councils should identify greenbelt opportunities to help meet their housing targets.

It has said brownfield and grey-belt land, such as wasteland or car parks, will be prioritised, and any development on greenbelt land would require 50% of homes to be classed as affordable.

A Ministry of Housing, Communities and Local Government spokesperson said: “We will reform the outdated compulsory purchase process to remove inflated values of land and ensure compensation paid to landowners is fair but not excessive. This is part of our plan to get Britain building again and deliver the homes the country desperately needs.”