Zimbabwe plans to increase royalty rates on platinum producers and introduce one for lithium miners from Jan. 1 as part of efforts to boost its coffers that have come under strain from weakening economic conditions.

The rate for platinum miners will double to 5% and a new rate of the same amount will apply to lithium producers, Finance Minister Mthuli Ncube said in his mid-term budget review presented to lawmakers in the capital, Harare, on Thursday.

“Mindful of the fact that the tax regime is the main instrument for sharing benefits from finite minerals and also provides an important source of government revenue, it is necessary to maximize revenue to the fiscus,” he said.

An accelerating shift to electric vehicles and soaring lithium prices have drawn investor interest to Zimbabwe. Chengxin Lithium Group Co. and Sinomine Resource Group Co. are setting up a joint venture to explore for the metal and Zhejiang Huayou Cobalt Ltd. plans to invest $300 million to develop its Arcadia lithium mine.

The southern African nation has the world’s third-largest known platinum reserves, after Russia and South Africa. Platinum producers in the country include units of Zimplats Holdings Ltd. and Anglo American Platinum Ltd.

Ncube announced the measures as he cut the nation’s economic growth forecast for this year to 4.6% from 5.5% at the end of last year, citing the global economic slowdown. Growth is being crimped by Russia’s war with Ukraine, the escalation of sanctions on Russia, a sharper-than-anticipated slowdown in China, and soaring inflation and a depreciating currency.

Zimbabwe’s annual inflation rate jumped to 192% in June, the highest level in more than a year, as food costs more than tripled. The increase in prices has been spurred by a sharp depreciation in the Zimbabwe dollar, which has lost more than 74% of its value against the US currency this year.

To boost growth and cushion the impact of the increased cost of living on public servants, the nation will increase expenditure to 1.9 trillion Zimbabwean dollars ($4.6 billion) from a previous estimate of 968 billion Zimbabwean dollars, Ncube said.