More than 1,000 voters were disqualified from voting in functional constituencies ahead of the Legislative Council election last September, the Registration and Electoral Office has revealed.
The figure is a three-fold increase in disqualifications compared with the 2008 election and can be attributed to revelations of vote-rigging last year.
There are 28 functional constituencies in Hong Kong based on different trade and professional sectors.
According to the law, the REO requests that bodies or institutions from the sectors provide updated member or employee status information before an election is held so that a voters' register could be compiled.
Once compiled, and the REO has received additional information about status changes, it will issue a reminder to those who are not qualified to vote.
Before last September's election, the REO sent out 1,120 letters, compared with 465 in 2008.
The information technology sector had the second biggest number of disqualifications, with 448 letters issued. In 2008, none of its voters were disqualified.
IT constituency lawmaker Charles Mok believed the sharp increase was the result of professional bodies scrutinising their memberships after the media exposed loopholes in the sector.
Members of certain IT bodies, such as the pro-government Internet Professional Association (iProA), were eligible to vote in the sector. But iProA was accused in 2011 of letting people whose memberships had lapsed to remain in the group.
"The voters' register relies heavily on the groups reporting voluntarily about their membership," Mok said.
"The REO should conduct random checks to ensure those non-members cannot vote."
A number of vote-rigging cases were revealed after the district council election in November 2011.
A man was jailed last October for a year and another for eight months for breaking the law.
The education sector recorded the highest number of disqualifications, rising from 234 to 502. Lawmaker Ip Kin-yuen said this was because many teachers switched jobs.
He said all registered teachers and permitted teachers could vote in the constituency, but
"it is possible that some young teachers leave the profession for other careers".
The Election Committee Subsector Election also showed a similar rising trend in 2011 as 318 voters were disqualified, up from 233 in 2006.