SYDNEY- India's head coach Ravi Shastri says his side will take no prisoners in their upcoming test series against Australia, who are still formidable opponents despite results going against them in the wake of the ball-tampering scandal.

The scandal, which occurred during the third test against South Africa in Cape Town in March, resulted in year-long bans to former Australia captain Steve Smith and vice-captain David Warner, with batsman Cameron Bancroft suspended for nine months.

Australia have struggled to recover from the crisis, losing a test series to Pakistan in the United Arab Emirates and being whitewashed 5-0 by England in a one-day international series in June.

They also lost 2-1 to South Africa at home in an ODI series earlier this month.

Shastri, however, believes Australia will still be strong in the four-match series that starts next month and being deprived of key players will not weaken them significantly on home soil.

"I always believe no team is weak at home," Shastri, whose side have never won a test series in Australia, told reporters in Brisbane on Sunday.

"We might have three or four players not playing when a team comes to India, but God forbid if anyone says it is a weak Indian team because you will be surprised."

Shastri said his side would be "taking no prisoners" in their approach to the series.

"We want to go out and put our best foot forward and focus on our game rather than what's happening outside," he added.

India will play a three-match Twenty20 series before the first test starts at Adelaide Oval on Dec. 6.

The Australia series will be the last chance in 2018 for Virat Kohli's men to match their formidable home form with success abroad and show the world why they are the world's top-ranked test side.

India, who last lost a test series at home in late 2012 against England, started the year with a 2-1 loss in South Africa but then thrashed debutants Afghanistan at home in a one-off test.

They then lost a five-match series 4-1 in England before thrashing West Indies 2-0 at home.

Kohli scored four hundreds during the team's last trip 'Down Under' and Shastri backed the batting ace to come good again.

"He loves coming to Australia, he's passionate about his game and the pitches here suit his style of play," former India all-rounder Shastri said. "Once you have done well in this part of the world you always want to come out and play well again.

"It's a great place to play cricket, they play it hard, the sporting public really appreciate good, tough cricket. It doesn't matter which side wins as long as there's competition."

(Reporting by Sudipto Ganguly in Mumbai ; editing by Toby Davis) ((sudipto.ganguly@thomsonreuters.com; +91 22 6180 7264; Reuters Messaging: sudipto.ganguly.thomsonreuters.com@reuters.net))