Jaitley is due to attend a World Bank meeting on Oct. 10-12 in Washington, where he is also expected to meet senior government officials. He was due to leave on Oct. 8.
"It seem doubtful that he would be able to take stress for the long journey to the U.S. and participate in the World Bank meeting," said a senior finance ministry official, adding the final decision would be taken in consultation with his doctors.
The 61-year-old lawyer, who also holds the defence portfolio in Prime Minister Narendra Modi's four-month-old government, had to skip a meeting of finance ministers from the Group of 20 nations in Australia this month.
Jaitley was expected to visit the Pentagon during his trip to Washington.
Jaitley was admitted to a private hospital in New Delhi on Sept. 1 for gastric bypass surgery to treat weight gain he has suffered because of a long-standing diabetic condition. He was re-admitted to hospital last week, a doctor who operated on him said.
Jaitley, who had heart surgery several years ago, was moved to the isolation ward in a government hospital on Sunday to reduce the number of people visiting him after he contracted an infection, doctor Pradeep Chowbey told Reuters.
"He has been lodged in the AIIMS hospital to ensure control over people visiting him - a reason for him getting the infection," said Chowbey, referring to the All India Institute of Medical Sciences.
A medical source said Jaitley's weak immune system was affected after he ate at a state dinner hosted during a visit to India by Chinese president Xi Jinping.
"He should have avoided that food, which was cooked hours before it was served. He needs to strictly follow the regimen and take proper rest for next few days," the source said.
Officials said Jaitley's absence from two key ministries for almost a month had begun to slow decision-making, including delays to appointments of officials such as the chief economic adviser in the finance ministry.
"We need a full-time minister to lead the ministry," said the finance ministry official, adding the government still had to start raising more than 584 billion rupees ($9.51 billion) through the sale of government stakes in state-run and private companies. He said minister's absence was also affecting work on a new goods and services tax, a key part of the minister's agenda. (1 US dollar = 61.4300 Indian rupee)