A proposal to amend a decades-old law that governs properties worth millions of dollars donated by Indian Muslims over centuries has triggered protests in the country.

The properties, which include mosques, madrasas, shelter homes and thousands of acres of land, are called waqf and are managed by a board.

The new bill – which introduces more than 40 amendments to the existing law – was expected to be tabled in the current parliament session after incorporating changes suggested by a joint committee of MPs.

But the committee is now set to ask for more time to submit its recommendations.

Prime Minister Narendra Modi’s government says that the proposed changes are necessary to root out corruption in the management of these properties and address demands for reform from the Muslim community.

But several Muslim groups and opposition parties have called the changes politically motivated and an attempt by Modi’s Hindu nationalist party to weaken the rights of minorities.

The bill was first introduced in parliament in August but then sent to a joint parliamentary committee for their recommendations.

In Islamic tradition, a waqf is a charitable or religious donation made by Muslims for the benefit of the community. Such properties cannot be sold or used for any other purpose – which implies that waqf properties belong to God.

A vast number of these properties are used for mosques, madrasas, graveyards and orphanages, and many others are vacant or have been encroached upon.

The tradition of waqf in India can be traced back to the Delhi Sultanate period in the 12th Century when the early Muslim rulers from Central Asia came to India.

The properties are now governed by the Waqf Act, 1995, which mandated the formation of state-level boards. These boards include nominees from the state government, Muslim lawmakers, members of the state bar council, Islamic scholars and managers of waqf properties.

The government says that the waqf boards are among India’s largest landholders. There are at least 872,351 waqf properties across India, spanning more than 940,000 acres, with an estimated value of 1.2 trillion rupees, ($14.22bn; £11.26bn).

Muslim groups agree that corruption is a serious issue in waqf boards – its members have been accused several times of colluding with encroachers to sell waqf land.

But critics also say that a significant number of these properties have been encroached by individuals, businesses and government bodies, which too requires immediate attention.

A report submitted in 2006 by the Justice Sachar Committee, formed by the earlier Congress party-led government to assess the socioeconomic conditions of Muslims in India – had recommended waqf reform, as it found that the revenues from the boards were low compared to the vast number of properties they managed.