Feb 22 (Reuters) - Brookfield Infrastructure Partners on Monday formally launched a hostile bid to buy Inter Pipeline Ltd with the same C$16.50-per-share offer that the Canadian oil and gas transportation company had rejected as inadequate weeks ago.

Earlier this month, Brookfield said it was willing to raise its offer to as much as C$18.25 per Inter share if the company comes to the negotiating table, but Inter turned it down and later launched a strategic review of options.

The current offer from Brookfield, which acquires and manages infrastructure assets, values Inter at C$7.08 billion ($5.62 billion).

The investment firm earlier this month also said it had acquired a 19.65% economic interest in Inter Pipeline, to become the top shareholder in the Calgary-based company.

Brookfield said on Monday that other shareholders now have until June 7 to accept its offer at the original C$16.50 per share with an option to take that amount in cash or Brookfield's shares.

Inter Pipeline said separately that its special committee is reviewing the offer and will make a recommendation within 15 days.

"It is the Board's duty to not only review this offer, but to pursue all available opportunities to unlock maximum value for our shareholders," the company said in a statement, urging shareholders to not take any action on the hostile offer.

Inter, whose assets include more than 7,000 km (4,300 miles) of oil pipelines, 5 million barrels of oil storage in western Canada and natural gas liquids processing plants, said on Thursday its formal review could include a possible "corporate transaction" but no decisions have been made yet.

Brookfield Infrastructure has engaged BMO Capital Markets and Barclays Capital Canada Inc to act as joint financial advisers.

($1 = 1.2599 Canadian dollars) (Reporting by Rithika Krishna and additional reporting by Shariq Khan in Bengaluru; Editing by Maju Samuel and Devika Syamnath)