MANILA - The Philippines confirmed on Thursday that 23 of 27 mines reviewed for compliance with state regulations will continue to operate, while the remaining four in the world's No. 2 nickel supplier that failed the audit could face closure.

The government review panel issued its final report after studying mines that were ordered closed or suspended last year by former minister Regina Lopez, a staunch environmentalist, in a move that upset the industry and led to her replacement.

The decision will bring more certainty for miners, along with moves by her successor as Environment and Natural Resources Secretary, Roy Cimatu, to wind back restrictions on small-scale mining projects and exploration permits.

However, mining remains a deeply contentious issue in the Philippines after past examples of environmental mismanagement.

Cimatu told reporters a decision on the fate of the four mines that failed the review of legal, technical, economic, social and environmental compliance - three nickel projects and a chromite mine - would be made as soon as possible.

"The DENR (Department of Environment and Natural Resources) will meet to decide whether to pursue the closure or give (them) a second chance," Wilfredo Moncano, head of the Mines and Geosciences Bureau, told Reuters.

Cimatu declined to identify the four mines because they have not been informed yet of the review outcome.

He said the final decision on the mines would be up to President Rodrigo Duterte, who warned miners to follow tighter environmental rules or shut down shortly after he took office in 2016.

Mining contributes less than 1 percent to the Philippines economy, with only 3% of the 9-million hectares identified by the state as having high mineral reserves being mined.

There are 50 operating mines in the Philippines, 30 of which extract nickel ore, most of which is shipped to top buyer China where it is used to make stainless steel.