One of Queensland's oldest races, the Weetwood Handicap, is to have its first date change in its 120-year history.

The Weetwood in Toowoomba was for many years run in conjunction with the annual agriculture show in late March or early April as was the case this year.

In a media release, Racing Queensland said the $150,000 Weetwood and the Toowoomba Cup would shift to September 26 in 2020.

Both races will now coincide with the city's Carnival of Flowers festival and serve as a key feature of a new-look calendar in the Sunshine State.

Racing Queensland chief executive Brendan Parnell said re-scheduling the Weetwood and Toowoomba Cup would pay dividends for the racing industry.

"We've long coveted a spring carnival of our own and in 2020 we will have one," Mr Parnell said.