Both the series would be tough but the one against Australia would be tougher as that side is rated the world's number one team, Sehwag said on the sidelines of a fitness camp for Asia Cup probables in Bangalore on Tuesday.
Asked about India's prospects against Australia, he said it depends on the form and how Sourav Ganguly-led team played in the coming Asia Cup and the tri-nation series in Holland.
"If we continue with the good form that we showed in the last season...like last year when we won against them...definitely this time also we will win the series (against Australia)," he added.
"We are working hard, and making all the efforts. But (then) it's cricket and anything can happen".
He stressed the need for India to beat Australia in the Holland event to gain psychological advantage which he said would be a plus point.
Sehwag said when India toured Australia, nobody expected them to do well. "But we were in great form, and we wanted to play well against Aussies in Australia.
When asked if he would say surpassing Brian Lara's world record 400 knock is one of his goals in the coming season Sehwag, who has a triple century to his credit, said: "I am not sure about it".