Jockey Craig Williams says neither history nor weight will stop Dunaden from becoming only the sixth horse to win the Melbourne Cup more than once.

And he says the seven-year-old is a better horse now than when he won last year's Cup - without Williams, who missed the ride through suspension.

Dunaden will have to overcome a record weight of 59kg - the highest since metric measures were introduced in 1972 - if he is to defend his crown on Tuesday.

Williams and Dunaden are also out to snare the Caulfield Cup-Melbourne Cup double and if he can steer the entire to another victory on Tuesday the French stayer would become only the 11th horse to capture the major races in the same season.

The only multiple Melbourne Cup winners have been triple winner Makybe Diva (2003-05), Think Big (1974-75), Rain Lover (1968-69), Peter Pan (1932 and 1934) and Archer (1861-62).

Dunaden won last year's cup with 54.5kg, beating Red Cadeaux into second by the narrowest margin in the race's history and will now line up against the fellow import 2.5kg worse off in the weights.

But Williams said Dunaden can win when he jumps from barrier 16 if he has his share of luck in the race.

"I believe that as long as he gets the right run in the race and he doesn't get any bad luck, I don't think the weight's going to stop him," Williams told radio station RSN.

He said Dunaden had improved from last year's Cup and even from last month's Caulfield Cup.

"I was pretty comfortable going into the Caulfield Cup and the way that he responded was great," he said.

"He came through the race so well and since then I've been down to Werribee to work him again and felt that he's improved more, which we were hoping and which he probably needed to do as well."

Williams was famously suspended and missed the ride on Dunaden last year having already won the Caulfield Cup with Southern Speed and the Cox Plate with Pinker Pinker.