Up to 3,000 Labour campaigners are expected to descend on Makerfield for Andy Burnham, prompting fears among organisers that the hordes of activists may end up overwhelming voters during Thursday’s byelection.

Local hotels are fully booked and party members are expected to be dispatched to polling stations, and to leaflet people waiting at bus stops and school gates to avoid swamping residents on their doorsteps.

Cabinet ministers are among the MPs who are expected to spend the day in the Greater Manchester constituency, where Burnham is seeking to defeat Reform UK’s Robert Kenyon.

“There is only so many times we can knock on doors on polling day without people getting too annoyed,” one MP said.

Backers of Burnham are expected to use the sheer numbers of activists and MPs doorstepping in Makerfield as proof that the mayor of Greater Manchester can re-energise the party to beat Reform UK – where the momentum will be crucial for him to then seek to immediately replace Keir Starmer as prime minister.

Some MPs and ministers arriving to campaign in the constituency over the past week are said to have sometimes been taken aback that there is little public-facing for them to do apart from dispatching leaflets through letterboxes. “There were just too many of them,” one said.

The campaign estimates that the number of volunteers – including hundreds of MPs – has meant each door in the constituency has been knocked at least six or seven times.

The number of volunteers who have signed up has been so vast that the Burnham campaign has organised three campaign centres beyond its headquarters in order to be able to handle the volume of MPs and activists who are arriving in the Wigan suburbs.

“It will be the operation that every Labour campaign has wanted to run but hasn’t had the bodies,” one organiser said. “A person on every polling station from open to close, school gates, station leafleting.”

All polls in the constituency have given Burnham a clear lead over Kenyon, though MPs who have visited the area in recent days say the race remains tight. One unknown factor will be the size of the vote for Rupert Lowe’s Restore party, which he set up as a rival to Reform and which may get as much as 10% of the vote.

Backers of Burnham are keen to prove the mayor can win without the need for Restore to split the vote on the right – or risk casting doubt over the symbolism of his victory.

“No 10 will be talking down the achievement of winning Makerfield,” one MP said. “Yet the result at the locals would equate to an 8,000 majority for Reform.”

Starmer has not campaigned in Makerfield, despite having promised to do so at the beginning of the campaign.

However, cabinet ministers including David Lammy, Bridget Phillipson and Jonathan Reynolds have been in the constituency in recent days, as well as the former health secretary Wes Streeting, who has said he also intends to challenge Starmer for the leadership.