The right to buy legislation will give community groups the right to ask for private or public land or buildings to be included in a list of 'assets of community value', and then be given time to raise cash to buy those assets when they come up for sale.
The right to challenge will give community organisations the right to bid to take over local services if they feel they can provide them more efficiently.
Community sector umbrella bodies warned that changes are needed to make the government’s proposals effective.
In a briefing document, the Development Trusts Association and Bassac, which are in the process of merging, said that for a right to buy to be effective, communities would need at least six months, possibly a year, to raise funds, rather than the present proposal for a moratorium period determined by the local council.
Community groups should also have a right of first refusal on public land, rather than having to compete on the open market, it said.
Both consultations run until 3 May.