India's influential but ailing finance minister Arun Jaitley announced on Wednesday that he would not serve in Prime Minister Narendra Modi's new Hindu nationalist government because of poor health.

Modi is set to be sworn in on Thursday after winning a second landslide election and should name his new cabinet shortly after.

Jaitley, 66, a key member of the last government, said in a letter to Modi he released on Twitter that he would “like to keep away from any responsibility” so he could concentrate on his health and treatment.

Jaitley underwent a kidney transplant in May last year and in February travelled to the United States for surgery after being diagnosed with cancer.

“I am writing to you to formally request you that I should be allowed a reasonable time for myself, my treatment and my health and therefore not be a part of any responsibility, for the present, in the new government,” he added in the letter.

Jaitley also hailed the “spectacular win” of Modi's right Bharatiya Janata Party (BJP) in the six-week election that ended last week.

The BJP swept 303 of the 542 contested parliamentary seats to win a second five-year term.

A lawyer-turned-politician, Jaitley guided the government's rollout of a complex nationwide tax and often acted as a spokesman on contentious issues.

Railways minister Piyush Goyal, who stepped in for Jaitley to present an interim budget in February, and BJP president Amit Shah are in contention for Jaitley's job, media reports said.

India is the world's sixth largest economy and although it has been growing at about seven per cent a year, it is showing signs of a slowdown.

Modi, 68, has invited the heads of countries who are in the Bay of Bengal Initiative for Maritime and Economic Co-operation (BIMSTEC) to the swearing-in.

India's archrival neighbour Pakistan is not a part of the alliance and so Modi avoided inviting Pakistan Prime Minister Imran Khan.