If the appeal succeeds, Tabcorp pointed out the matter would be referred back to the Australian Competition Tribunal for review, "rather than restarting proceedings."
The company said both businesses remained "committed to the transaction", and would seek to have the hearing fast-tracked in the Federal Court of Australia.
"The ACCC's application will impact the timing and implementation of the transaction, though the precise impact will not be known until the court has considered the matter," Tabcorp said.
"Tabcorp considers that implementation remains achievable in the last quarter of 2017."
Last month, the tribunal rejected a litany of concerns raised by the ACCC and rival betting companies that the tie-up would lead to a lessening of competition and that the merged entity would have too much power in dealings with pubs and clubs.
Federal Court Justice John Middleton found the merger would be substantially beneficial, and that the proposal had "overwhelming" support from the rest of the industry.