Saudi Arabia’s planned introduction of a 2.5% tax on undeveloped urban land is set to rake in SAR75 billion ($20bn) a year for the government, the Saudi Gazette reported.

The legislative Shura Council this month endorsed a 2.5% tax on undeveloped plots, in a move designed to ease the housing crisis in the kingdom. The proposed legislation still requires approval by the Saudi king.

Shura Council President Abdullah Al-Sheikh reportedly said that details such as the time frame for implementation have not been stated as yet, but that the new tax would be applied in stages.

According to the Housing Ministry at least 40% of urban land in Riyadh was left undeveloped in 2013, while the government is spending billions to build outside city limits. The housing shortage across the kingdom is estimated at 1.5 million units.

If approved the tax “will bring SR75 billion to the government coffers”, the Saudi Gazette reported, quoting real estate experts.

Mohammed Al-Dossary, one property expert quoted by the newspaper, said the tax would “bring at least SR50 billion to the state coffers annually.”