Big Orange is likely to miss the Irish St Leger with connections wary of his Melbourne Cup handicap.

The Michael Bell-trained five-year-old finished fifth in the 2015 Cup carrying 55.5kg.

He has shone at his past two starts, winning the Princess of Wales's Stakes for the second successive season at Newmarket before defending his crown in the Goodwood Cup.

Bell said he would talk to owner Bill Gredley about the St Leger for which Big Orange is on the third line of betting with Melbourne Cup favourite Order Of St George heading the market.

"I've got to talk again to Mr Gredley, but we are looking at saving our powder," Bell said.

"We are keen to go (to Australia) and we are waiting to see what weight he is given before loading the cannon.

"But Mr Gredley will make the final call."

Nominations for the Melbourne Cup are announced on Tuesday with the weights released on September 13, two days after the Irish St Leger.