Mexico hopes to attract $620 million in investments when it auctions off onshore oil and gas fields as part of its historic sector opening to private companies, officials said Tuesday.

The 26 land fields are the first onshore projects being offered by the government, which has already set a July date for auctions of offshore shallow-water projects.

Energy Minister Pedro Joaquin Coldwell said the onshore projects are in the northern states of Nuevo Leon and Tamaulipas, the eastern states of Veracruz and Tabasco, and the southern state of Chiapas.

They will bring in $620 million in investments over five years, producing 36,000 barrels of oil per day and more than 223 million cubic feet of gas per day, Coldwell told a news conference.

The 2013 reform aims to reverse falling oil production by inviting foreign investors back into the country for the first time since the nationalization of the industry in 1938.