Soosa Rama will step up in distance in a bid to take her winning streak to four at Flemington on Saturday.

Soosa Rama completed a hat-trick of victories when she came from last to circle her rivals and score over 1200 metres at Moonee Valley on March 14.

The filly's trainer Colin Little said that effort convinced him and jockey Damien Oliver that Soosa Rama needed to be stepped up in distance if she was to continue her unbeaten run.

"Olly just said she had no early pace," Little said.

"In her other runs she has shown pace but bad barriers have meant she has had to go back."

Mark Zahra replaces Oliver who will be in Sydney for the Golden Slipper meeting at Rosehill.

Zahra steered Soosa Rama to victories at Cranbourne and Moonee Valley at her first two outings but will have to contend with a wide barrier draw in Saturday's Prudential Plate (1400m).

Little said the gate would give Zahra little option but to ride the filly quietly.

"With the 11 barrier, she is going to have to go back again," Little said.

The three-year-old was set to head to the spelling paddock after her last win but Little said Soosa Rama surprised him with her recovery.

So much so that the trainer will consider pushing on to the Adelaide carnival.

"We thought for a week after her last race she might have had enough but she's just thrived," Little said.

"We're not sure where she'll go next but there's a race in Adelaide for her but we'll see how she goes."

Soosa Rama's three wins have not convinced bookmakers to make her the opening favourite for the Prudential Plate.

The Peter Moody-trained River Delta is at $2.70 on the strength of her debut win at Yarra Glen while Soosa Rama is a $3.20 second pick.