The final leg of the National Apprentices Race Series (NARS) will be run at Doomben on Wednesday with the host State, Queensland, having no chance of defending its crown.

Queensland claimed the coveted NARS title for the first-time last year when the series came down to the final day at Sandown where Angela Jones sealed victory for the Maroons.

This year's series began at Murray Bridge in South Australia last month with Queensland being represented by Rockhampton's Tahlia Fenlon.

North Queensland apprentice Gabrielle Semmens then made the long trip to Hobart for the second day while Brisbane's Emily Lang headed off to Perth for the third leg of the series.

Rockhampton's Brooke Johnson represented Queensland in Darwin last week but failed to make any inroads in the title race where South Australia leads with 37 points, six points clear of the Northern Territory on 31 points while Tasmania and West Australia are equal third with 25 points.

Queensland is currently in last place on 10 points..

Racing Queensland's Senior Apprentices Coach Shane Scriven believes the series is still wide open.

"Queensland is the last leg but unfortunately we can't win," Scriven said.

"But it's still wide open between the other States."

The final two heats of the NARS will be run at Doomben with favourites South Australia represented by Rochelle Milnes.

The Port Lincoln-born Milnes has a great chance of claiming the NARS crown for South Australia when she partners the Brett Baker-trained In The Picture in the Maiden Plate over 2000 metres.

She will get a second bite aboard Zelgaria for the Matt Dunn stable in the Class One Plate over 1200 metres.

In The Picture has been placed three times from 12 starts including her past two starts at Toowoomba and Ipswich where she finished third in a 2150-metre maiden behind the Bevan Laming-trained Subaqua.

Zelgaria has had two starts back this campaign at Grafton and is coming off a last start fifth in an 1175-metre Class One on March 7.

NARS was first staged in 2008 and is Australia's premier competition for apprentice jockeys with points awarded in each leg of the series.

The winner receives seven points while four points are awarded to the second horse, two points to the third placegetter while all unplaced riders receive one point each.

The series draws together apprentice riders from around the country to represent the state in which they are registered to ride.