Labour members and councillors across the country have accused the party of skewing the selection of candidates in safe seats where the incumbent MP is retiring or has resigned.

More than 30 Labour seats have been up for grabs for the next election, significantly more than the 13 that were vacated before the 2017 vote.

Activists have complained that longlists drawn up by the party’s ruling national executive committee (NEC) under a fast-track process to prepare Labour for an election are designed to increase the chances of success for favoured candidates.

Members in Ealing North in London are among those to have written to the Labour party’s general secretary, Jennie Formby, to register their dismay at the longlists produced for their constituencies.

“The list is not only extremely short but it has omitted all Ealing North residents, including several Ealing North councillors, two of whom have been PPCs [prospective parliamentary candidates] before. With only two female candidates, it also clearly lacks gender balance,” the letter read.

“There is a widespread belief among Ealing North CLP [constituency Labour party] members that the NEC has decided on an outside candidate to be the next Ealing North MP and many strong local candidates have been omitted.”

A Labour member in the Ealing North constituency, which has been represented by Stephen Pound since 1997, said the longlist had managed to enrage both the right and the left of the party. “Jeremy Corbyn promised a new era of people’s democracy and respecting members. But this is like control-freakery of the Blair era,” they said.

About 17 Labour MPs have announced they will not stand again, with at least another four resigning after being suspended. A further 10 resigned in order to stand for different parties or as independents, citing the party’s Brexit position and approach to antisemitism allegations. Many decided to resign under the threat of deselection by their local parties.

This month the NEC agreed on a fast-tracked selection process for new candidates in order to ensure they were in place in the event of a snap general election.

The new process took the responsibility for drawing up a longlist of candidates out of the hands of local parties and gave it to the NEC. Shortlists are finalised by a panel comprising NEC, regional board and local party representatives before they are put to local members.

Members in Coventry North West, which has been represented by Geoffrey Robinson since 1976, held an emergency meeting on Wednesday night after a longlist of candidates was leaked to a local journalist and included no local councillors. About 50 people attended.

Robinson has submitted a formal complaint to the party about the “shambolic and underhand nature” of the selection process, while Coventry Momentum tweeted: “Local candidates in #Coventry need to be selected by local members. We do not want a list of candidates imposed on us, this is not what democracy looks like.”

Chris Jones, the chair of the constituency party, said: “It seems to me that they are trying to skew the longlist so it becomes inevitable that certain favourites are chosen.”

Damian Gannon, a local member, said: “This isn’t about left and right, it’s about central control and local democracy. We know that all leaderships have done stuff like this in the past, but they’ve only done it in one or two seats at a time. Now they’re trying to do it in a load of seats across the country.”

There are similar complaints from members in Enfield North, which is currently represented by Joan Ryan, who left the Labour party in February to join the Independent Group for Change. Ed Poole, the vice-chair of membership in the constituency party, said it had been clear that members wanted local Corbyn-supporting candidates on the long list, but there were none.

“The candidate with the highest number of endorsements from nominations hasn’t been longlisted,” he said. “I got nominated by the biggest ward, so was arguably third out of 61 candidates. I’m not longlisted.

“We certainly don’t feel the membership has been reflected at all in this process. We were supposed to have membership democracy. We were supposed to have grassroots movement. We were supposed to have more and more say.”

He added: “It looks like having friends in high places is useful and having the support of local members is not.”

An NEC source said the party had been flooded with applications when the selections opened. “There are so many excellent candidates to choose from, forcing us to make really tough decisions,” they said. “So we’ve longlisted the candidates with the best applications. It’s as simple as that.”

A Labour source said: “The purpose of longlists is to narrow the field, so clearly not everyone can be on that list. These are hotly contested seats with many high-quality applications and of course unsuccessful candidates will be disappointed.”

A party spokesperson said: “These fast-tracked selection processes are the only way to ensure democratic selections in such a short space of time. Members will democratically select their candidates with local members on the shortlisting panels.

“An election could be round the corner, so we are moving quickly to make sure we have candidates and campaigns ready to go to defeat the Tories so we can end austerity and transform society.”

Additional reporting by Martha Brennan.