March 4 (Reuters) - Canadian midstream company Enbridge ENB.TO said on Tuesday that it plans to invest $2.5 billion in its liquids and natural gas systems, with $2 billion allocated to its Mainline network through 2028.

The Mainline is North America's largest crude oil pipeline network and transports light and heavy crude oil, natural gas liquids and refined products from Edmonton, Alberta, to various markets in Canada and the U.S. Midwest.

Enbridge moves about 40% of crude oil produced in North America.

The announcement coincides with U.S. President Donald Trump's 10% tariffs on Canadian energy imports coming into effect. The company had said in its fourth-quarter earnings that it did not see its financial guidance being materially impacted by the levies.

"All four of our growing franchises are opportunity-rich, and we're seeing approximately $50 billion of combined new growth opportunities through 2030," CEO Gregory Ebel said in Tuesday's investor day plan.

The company said it would also invest $400 million in Birch Grove, a 179 million-cubic-feet-per-day expansion of the T-North section, which is part of its Westcoast Pipeline.

The expansion is expected to enter service in 2028 and would increase T-North's total capacity to 3.7 billion cubic feet per day.

The 2,953-km-long (1,834 miles) Westcoast Pipeline stretches from Fort Nelson in northeast British Columbia to Gordondale near the BC-Alberta border, south of the Canada-United States border, and currently has a capacity of 3.6 bcfpd.

Enbridge also sanctioned $100 million in February to expand the T15 project in North Carolina - a 45-mile natural gas pipeline that will supply Duke Energy's DUK.N Roxboro plant - and aims to double the capacity of natural gas delivered to it.

Both T15 phases are expected to cost a total of $700 million and will become operational in 2027 or 2028, the company said.

(Reporting by Seher Dareen in Bengaluru; Editing by Pooja Desai)

((Seher.Dareen@thomsonreuters.com; If in India call +91 74832 70128;))