SYDNEY (Reuters) - Australia's antitrust watchdog on Thursday gave the green light to a A$9.1 billion ($6.79 billion) buyout of rail freight giant Asciano Ltd (>> Asciano Ltd) by a global consortium led by Canada's Brookfield Asset Management Inc (>> Brookfield Asset Management Inc).

The Australian Competition and Consumer Commission (ACCC) had been concerned the deal would give Asciano's new owners, which include Australian stevedoring company Qube Holdings Ltd (>> Qube Holdings Ltd), too much control of the freight market.

ACCC Chairman Rod Sims said the regulator had concluded there was "not likely to be a substantial lessening of competition in any market” after the deal was restructured to address officials' concerns.

Investors sent Qube shares to a two-month high of A$2.505 on the news. At 0120 GMT, they were up 3.2 percent at A$2.44 in a firm Australian market <.AXJO>. Asciano shares were 0.9 percent higher in late morning trades.

"To come through with no objections, no further delays, was a little bit of a surprise," said John Corr, chief investment officer at Aurora Funds Management.

"Qube shares probably suggest it's a good deal for them."

The go-ahead came as a relief for Asciano shareholders following a year-long takeover battle that began with Brookfield's initial solitary bid of $6.8 billion last July. The ACCC could have mounted a legal challenge, a move that would have hit the company's share price.

"The decision by the ACCC is clearly a major milestone in the process of acquiring these important businesses," Qube said in a statement.

The takeover must still be approved by Australia's Foreign Investment Review Board but analysts expect it to get the nod as the restructured deal keeps Asciano's strategically important ports out of Chinese hands.

Brookfield and Qube joined forces in February to make a joint offer for Asciano's port assets only, leaving the railways to China Investment Corp (CIC) [CIC.UL] and others.

Asciano shareholders in June voted in favor of the buyout.

(Additional reporting by Tom Westbrook; Editing by Stephen Coates)

By Swati Pandey