Saudi Arabia has established a $182 million mineral exploration incentive programme, a senior government official said on Wednesday, part of efforts to build an economy that does not rely mostly on oil.

The kingdom is pushing to expand its mining sector and tap vast reserves of phosphate, gold, copper and bauxite.

"This programme will de-risk investments in our exploration, securing to enable new commodities, green field projects and junior miners," Minister of Industry and Mineral Resources Bandar Alkhorayef said, speaking at the Future Minerals Forum.

Deals worth 75 billion riyals ($20 billion) are expected to be signed in Riyadh during this week's industry event, he added, announcing the fifth and sixth rounds of a licensing programme offering access to 33 exploration sites this year.

Saudi Arabia, the world's top oil exporter, is midway through an economic transformation plan known as Vision 2030 to diversify income sources away from hydrocarbons and develop sectors such as tourism, industry, and mining among others, to bolster non-oil GDP.

The Gulf state has revised upwards estimates for its untapped mineral resources to $2.5 trillion, from a 2016 forecast of $1.3 trillion. Alkhorayef said this was based on 30% of the Arabian shields exploration, suggesting there is more to be discovered.

Ma'aden, the flagship Saudi mining company, is 67% owned by the Public Investment Fund (PIF), the kingdom's sovereign wealth fund, and is at the forefront of developing the sector domestically as well as investing in assets abroad.

"We have the largest exploration program in the world...we look at mining not only (as) mining for minerals and mining resources but also data mining," Yasir Al Rumayyan, governor of PIF, said at the forum on Wednesday.

Separately, the Ministry of Industry and Mineral Resources announced its list of preferred bidders in the fourth series of mining licensing rounds, part of the Accelerated Exploration Program initiative, according to state news agency, SPA.

Saudi Arabia plans to award over 30 mining exploration licences to international investors this year, and could offer larger exploration areas of more than 2,000 kilometres for each licence. ($1 = 3.7502 riyals)

(Additional reporting by Federico Maccioni, Ahmed Elimam, and Nayera Abdallah in Dubai; Writing by Rachna Uppal; Editing by Louise Heavens and Ros Russell)