TORONTO (Reuters) - Brookfield Property Partners said on Monday it will acquire the 49 percent of Brookfield Office Properties (>> Brookfield Office Properties Inc.) it does not already own for $5 billion in a deal that would consolidate the companies' $45 billion in real estate assets.

The $19.34-a-share cash and stock offer, which represents a 15.3 percent premium over Brookfield Office Properties' closing price on Friday, drove shares of the target up 13.5 percent to $19.03 in midday New York trading.

Both companies are subsidiaries of Toronto-based Brookfield Asset Management (>> Brookfield Asset Management Inc.), which manages about $175 billion in power, property, infrastructure and private equity assets.

Brookfield Asset spun off Brookfield Property earlier this year to hold its commercial property assets, including its 51-percent stake in Brookfield Office Properties, which owns such famous properties as the former World Financial Center in New York and First Canadian Place in Toronto.

"We believe this transaction will consolidate our global office properties under one platform and substantially increase Brookfield property Partners' public float which should help accelerate our growth strategy," said Ric Clark, Chief Executive of Brookfield Property.

Shareholders can elect to receive either one limited partnership unit of Brookfield Property Partners or $19.34 in cash, with the total cash component of the deal not to exceed $1.7 billion, Brookfield Property said.

Brookfield Property units were up 8 Canadian cents at C$20.08 on the Toronto Stock Exchange. The company said it will finance the cash portion of the offer through an acquisition facility with a syndicate of banks.

The combined entity will hold more than 330 million square feet of office, retail, industrial and residential assets across four continents, the companies said.

(Reporting by Cameron French, editing by G Crosse)