North Atlantic Potash and Rio Tinto have found a large potash field south-east of Regina. (CBC)

Two major potash companies have discovered a lucrative potash deposit near the village of Sedley, 50 km south-east of Regina. 

North Atlantic Potash and Rio Tinto said the KP 405 potash field contains 329-million tons of potash.

Rio Tinto calls the find a Tier 1 discovery, meaning the find is one of the top tier potash deposits in the world.

"It's large," North Atlantic Potash CEO David Waugh said.

He said if a three-million ton per year mine was built on the site, the deposit would last for more than 100 years.

"We're at fairly early stages," Waugh said, adding that the next step would be to perform pre-feasibility studies to discover if building a mine would be profitable.

A 'go-forward' decision on building the solution potash mine should come in the next two years.