Racing Victoria has expressed its disappointment with the decision by the Australian Competition Tribunal to approve the merger between wagering companies Tabcorp and the Tatts Group.

The only condition imposed by the ACT on Tuesday was that Tabcorp must press on with the already agreed sale of its Queensland gaming machine monitoring business.

"We're disappointed the Australian Competition Tribunal has not accepted the genuine concerns of Victoria's three racing codes to the proposed Tabcorp merger with Tatts Group, granting approval with one condition unrelated to racing," RV chief executive Giles Thompson said.

"We note the Tribunal will hand down their reasons for decision on Thursday and we look forward to reading these to best understand their position before more broadly reviewing the possible implications of this decision on the Victorian racing industry.

"Our primary concern has been the potential negative impact the merger will have on competition for the next Victorian wagering licence.

"The more competition there is, the greater the opportunity to grow investment in thoroughbred racing in this state."

The Victorian wagering licence expires in 2024.

"Racing Victoria enjoys a strong relationship with Tabcorp, our joint venture partner, and have done so over a long period of time," Thompson said.

"We are committed to working closely with them to ensure that the Victorian TAB competes effectively and that our industry expands for the betterment of all stakeholders."

The ACT made its decision public ahead of its formal determination on Thursday after shares in both companies were placed in a trading halt.