Last week, the Supreme Court found Chinnicha guilty of filing a false asset statement and barred her from holding office for five years.
“The by-election must take place within the deadline regardless of an appellate review,” she said.
She said Chinnicha had a right to try to overturn her verdict but at the same time the EC could not wait for the outcome of the appellate review due to time constraints.
The Pheu Thai Party will not nominate its candidate to replace Chinnicha before the completion of the appellate review, party spokesman Prompong Nopparit said.
Prompong said he was confident Chinnicha could clear her name based on fresh evidence.