The Modi government has the required number of votes to pass the Goods and Services Tax (GST) Bill in the Rajya Sabha, said finance minister Arun Jaitley.

Doubts over the passage of the key tax bill have risen in the wake of the Bharatiya Janata Party (BJP)-led alliance's defeat in the recently-concluded assembly elections in Bihar.

The GST, which is considered as one of the crucial economic reforms in decades, may be implemented anytime in 2016 after the bill is approved, said Jaitley.

"The day it is discussed and put to vote in Rajya Sabha I have not the least doubt that it will be approved," Jaitley said in the interview to Bloomberg TV.

"We have numbers on our side," he said.

The bill will again be tabled before the Rajya Sabha when the Parliament's winter session starts next week.

In the monsoon session of Parliament, the Modi government was forced to delay the landmark GST Bill, after facing strong opposition in the Rajya Sabha, where it does not have a majority.

Jaitley said that the BJP's defeat in Bihar state polls "wouldn't affect the passage of GST."

"As a consumer of goods, Bihar stands to benefit from the new destination tax," he said.

Key reforms bills like Land Acquisition bill and Goods and Services Tax (GST) Bill have stalled in Rajya Sabha, where the ruling BJP doesn't have a majority due to "obstructionist opposition", Moody's Analytics had said in a report last month.

Jaitley criticised the Congress party for "playing hide and seek" in voting for GST approval, adding that Modi's position in the Rajya Sabha will see an improvement after April 2016.

"It's a transaction tax which can get into operation as soon as the Constitution allows," Jaitley said. "Once it's put to vote I have all the supporting legislation drafts ready."