The Electoral Commission has criticised the amount of time it took to hold the Glasgow North East by-election.
The watchdog said November's poll to replace former speaker Michael Martin could have been held much earlier.
It called for rules to be changed after voters in the constituency went without an MP for almost five months.
The commission also raised concerns about how the Labour Party handled its postal vote application forms in the run-up to the ballot.
The by-election was prompted in May, at the height of the Westminster expenses scandal, when Mr Martin announced he would be quitting the House of Commons.
But the resultant by-election did not take place until 12 November.
The Westminster summer recess began in July, during which time the writ for the by-election could not be served.
The Commons did not sit again until October, with the writ finally being moved on 16 October.
That was 116 days after Mr Martin left the seat and the longest delay of its kind in 35 years.
The poll was eventually won comfortably by Labour candidate Willie Bain, with the Scottish National Party in second place.
In its findings, the Electoral Commission said: "The UK parliament should reconsider the procedures for calling a UK parliamentary by-election to ensure that electors have an opportunity to elect a new MP promptly.
"The length of the vacancy in the Glasgow North East constituency meant that people in the constituency were not represented in the UK parliament for more than four and a half months."
The commission said it would have been possible to identify a much earlier date and to plan the vote within a shorter period of time.
Voters in two other constituencies also face a long wait for new MPs because of the convention that by-elections are not usually called in the months leading up to a general election.
No writs have been moved to replace the North West Leicestershire MP David Taylor, who died on Boxing Day, or Iris Robinson, who resigned as MP for Strangford on 13 January.
Andy O'Neill, head of the Electoral Commission's Scotland office, said the Scottish Parliament and the Welsh assembly had a "clear set of rules within which they have to have a by-election within three months".
He said: "The UK parliament should review its procedures and it should decide whether or not it changes its rules."
The Electoral Commission has also raised concerns with the Labour party about its handling of postal vote applications at the Glasgow North East poll.
The commission said Labour collected postal vote applications from constituents but did not submit them until close to the deadline, even though some had been signed by electors more than a month earlier.
A voluntary code of conduct requires parties to submit them within two working days of receipt.
The commission added: "We have had further discussions with the political party concerned to reiterate these points and we have been assured they will have the appropriate procedures in place for future elections."
SNP MP Stewart Hosie accused Labour of a "blatant breach" of the code of conduct on postal voting.
He added: "The people of Glasgow North East were left without an MP for an astonishing 142 days because of the shocking arrogance of the Labour Party who put their electoral convenience ahead of the needs of the local community.
"Any future government must heed this warning. The SNP will continue to push for timely elections so this situation is never replicated."
But a Labour spokesman said: "Shortly before the deadline for applications, Labour wrote to all our known supporters and encouraged them to fill out and return a postal vote application form.
"Many hundreds of people did this but this was during a national postal strike which the electoral commission has failed to identify."
The spokesman also said that if the writ for Glasgow North East had been moved before the recess, the by-election would have been held during the Glasgow school holidays.