MEXICO CITY, Nov 8 (Reuters) - Mexico needs to drastically ramp up energy investments to combat bottlenecks affecting private industry, the Chief Executive of steelmaker Ternium said on Wednesday.

"The public sector is not investing," CEO Maximo Vedoya said in a panel hosted by regional steel association Alacero in Sao Paulo. "In energy transmission and distribution, massive investments are critically needed."

In Mexico, state-run energy producers and distributors have dominated the market since President Andres Manuel Lopez Obrador, an energy nationalist, rolled back previous measures which had liberalized the industry.

"Mexico needs to change this," Vedoya said, first urging public investments in energy transmission and distribution, then arguing for "a circumstance in which the private sector can invest" as well, including in clean energy.

President Lopez Obrador has poured public funds into heavily indebted and heavily polluting state oil producer Pemex during his administration, with a massive new refinery set to reach full capacity by the end of the year.

Lopez Obrador's term comes up next year. "With that - and I'm really optimistic about it - I think part of (Mexico's energy policy) could change," Vedoya said.

Ternium is currently constructing a $2.2 billion steel plant in northern Mexico, a strategy to comply with regional trade pact requirements.

Steel is one of the most carbon-intensive construction materials.

The plant will include a direct reduced iron (DRI) module, which Ternium plans to ready to switch from natural gas to green hydrogen "when feasible." (Reporting by Kylie Madry; Editing by David Gregorio)