Thousands of people are expected to descend on the Welsh parliament on Wednesday in protest at a proposed overhaul of farming subsidies they say threatens the industry.

Welsh farmers objecting to the Welsh Labour government’s proposals to require more land to be set aside for environmental schemes have held a series of protests across the country in recent weeks.

The latest demonstration outside the Senedd in Cardiff Bay on Wednesday is expected to be the largest yet, with thousands of people set to attend.

South Wales Police has said it is aware of the protest and asked those coming not to bring tractors.

The protesters are objecting to the sustainable farming scheme (SFS), which is currently under consultation, which would require 10% of a farmer’s land to be covered in trees in exchange for future funding.

Farming leaders say the scheme could result in 5,500 job losses.

The Welsh government insists it is listening to farmers’ concerns and changes can be made.

Those demonstrating have seen the support of the prime minister, Rishi Sunak, who told a gathering outside the Welsh Conservative conference last week that “we’ve got your back”.

Speaking ahead of the demonstration, Andrew RT Davies, leader of the Welsh Conservatives, said: “Farmers in Wales are sending the message that enough is enough.

“The Sustainable Farming Scheme will have a devastating impact on our farming communities, and farmers are rightly not prepared to take it lying down.”

Rhun ap Iorwerth, leader of Plaid Cymru, has said the government should pause introducing the scheme and reflect on the arguments that have been made during the consultation.

A Welsh Government spokesperson said: “Farming is very important to Wales and our economy and we want a successful future for Welsh farming.

“We have had a seven-year conversation with farmers to design future farming support and we are committed to continuing to work with farmers to develop the Sustainable Farming Scheme.

“This is a genuine consultation and no decisions will be taken on any element of the proposal, including how we achieve the requirement for habitat and trees, until we have conducted a full analysis of the consultation responses.

“We have been clear we expect changes to be made following the consultation, and we will continue to listen.

“The First Minister and Rural Affairs Minister provided an update yesterday on a number of key areas to support the sector.”

Superintendent Esyr Jones said: “South Wales Police respects the right to peaceful protest and we are in discussions with the organisers to ensure that the protest takes place safely, lawfully with minimum disruption to the wider public.

“While there is an agreement to facilitate protest activity outside the Senedd, I would urge protesters not to bring tractors or other agricultural vehicles to the protest. There are concerns that they pose a risk to the safety of other road users and restrict the movement of emergency services in a busy city environment.”