He said officials at polling stations had already tested the pens being used after rumours were spread on social media.
However, if the voters still lacked confidence, they could bring their own pens to the polling stations, he said.
There were rumours on social media networks that the pens at Bangkok’s polling stations had ink that would disappear within 15 minutes.
Last week, Bangkok Metropolitan Administration permanent secretary Silapasuay Raweesaensoon had warned Facebook users not to share false information about the use of pens with disappearing ink.
Silapasuay said the pens that would be used at 6,149 polling stations in Bangkok are normal ballpoint pens whose ink cannot vanish.