The Newark by-election faces a greater risk of a legal challenge because of "inadequately performing Electoral Commission officials", a local council chief has said.
Andrew Muter, chief executive of Newark and Sherwood district council, hit out at the elections watchdog for not providing clear guidance on how to hold the by-election.
The Newark contest is the first parliamentary by-election since the coalition's Electoral Registration and Administration Act 2013 came into force. It changes the gap between the close of nominations and the date of the poll - but when it came to implementing the new rules, Muter found his elections officer was struggling.
"Following receipt of the writ I clocked the furrowed brow of my elections manager and asked him where we might turn for advice and guidance in our moment of need," Muter wrote in his column for the Municipal Journal newspaper.
"The obvious answer was the Electoral Commission whose role in giving returning officers advice is proudly heralded on their website.
"All guidance on running parliamentary elections from the website had been removed because of the change in legislation. Unhelpfully, they had not yet produced any new guidance."
Muter said the short notice of the by-election, combined with the two bank holidays in the election period, meant "it's easy to get things wrong, and getting them wrong can result in an unwelcome appearance in court".
He made clear his resentment of the fact that the Electoral Commission is empowered to cut the fees of poorly performing returning officers - and suggested ministers should have found a way of cutting the salaries of staff at the watchdog.
"The fundamental guarantee which underpins our electoral system is the obligation on those conducting elections to act fairly and lawfully and this is underpinned by direct accountability to the courts," Muter added.
"The insertion of the Electoral Commission between election officials and the courts and the dabbling of the Cabinet Office in electoral matters only serves to undermine this fundamental strength in our system."
The Electoral Commission said it had been in contact with the officials managing the Newark by-election to ensure the rules were followed.
"Parliamentary by-elections naturally place pressure on elections staff, but what's absolutely vital is that voters' and campaigners' needs are met," a spokesperson said.
"That's why our local team got in touch with the Newark elections team as soon as the writ for the by-election was issued.
"The Returning Officer is responsible for preparing the election timetable. While the Newark elections team did not asked for our advice beforehand, as soon as we saw the timetable didn't fully reflect the bank holidays, we contacted them to help them understand what they could do about this.
"The Electoral Commission will continue to support to the returning officer and his staff, and have most recently been in contact to confirm the steps that will be taken to rectify an error in postal ballot packs."
The Newark by-election will take place on June 5th. It follows the resignation of former Conservative MP Patrick Mercer, who quit after being implicated in a lobbying scandal.