Onchan commissioners say everybody who’s eligible should be able to vote this week – despite problems at the Post Office.
The local authority says issues with sorting equipment meant not all polling cards were issued on Friday.
However, the commissioners say all cards will be posted and should be received before polling day on Thursday.
Voting for one seat takes place between 8am and 8pm at The Hub on School Road in Onchan – the by-election being fought by three candidates was sparked after the resignation of Fenella Logan.