"New Bangladesh was born on August 5, not August 8," National Citizen Party (NCP) leader Hasnat Abdullah has said.
He made the remark in a post from his verified Facebook profile on Thursday.
He wrote: "The government’s attempt to appropriate the achievements of the general student masses on August 5 will not be accepted."
Earlier on Wednesday, the government declared August 8 as "New Bangladesh Day."
According to an official press release, the government announced August 8 as "New Bangladesh Day" and decided to include the date as a category B day in the list of national and international observances to be marked annually.