Oct 26 (Reuters) - New Zealand's Infratil Ltd said on Monday it would buy up to a 60% stake in Australian diagnostic imaging business Qscan Group Holdings Pty Ltd from Quadrant Private Equity for A$330 million ($235.46 million).

The infrastructure investment firm, which is also listed in Australia, said it made the offer together with the Morrison & Co Growth Infrastructure Fund, which has conditionally offered to buy up to 15% of Qscan.

"Qscan provides a high-quality entry point into a sector with structural long-term growth and potential to scale into a leading healthcare infrastructure platform," said Infratil Chief Executive Marko Bogoievski.

Hospital operator Ramsay Health Care was also reported to be bidding for Qscan, which owns more than 70 clinics in Australia, according to The Australian Financial Review.

The existing doctor and management shareholders will retain ownership of at least 25% of Qscan if the acquisition advances, Infratil said in a statement.

Quadrant Private Equity did not immediately respond to a Reuters request for comment.

($1 = 1.4015 Australian dollars) (Reporting by A K Pranav in Bengaluru; Editing by Alison Williams and Diane Craft)