BERLIN (Reuters) - German arms group Rheinmetall posted a 60% rise in first-quarter profit on Tuesday, as the joint manufacturer of Leopard tanks rides a defence spending boom triggered by Russia's invasion of Ukraine.

However, Rheinmetall's earnings were below consensus forecasts, Stifel analyst Alexander Wahl said, and its shares were seen 1% lower in early market trading in Frankfurt.

Rheinmetall, whose market value has more than quadrupled since the war in Ukraine, is seeing a sharp increase in orders as Western governments look to replenish their stocks after supplying substantial amounts of arms to Kyiv.

"Rheinmetall is needed by a large number of nations, now and in the future, to satisfy the sharp rise in demand for military equipment," its CEO Armin Papperger said in a statement.

The Duesseldorf-based firm's quarterly operating profit was 134 million euros and sales 1.58 billion euros, both below a company-provided consensus estimate of 143.4 million euros and 1.68 billion euros respectively.

Sales climbed 16% in the three months from January through March compared with the same period last year.

Rheinmetall is set to get orders worth as much as a third of the 100 billion euro ($108 billion) special defence fund introduced by Germany, Ukraine's second-biggest supporter, shortly after the Russian invasion in 2022.

Meanwhile, the European Union is trying to ramp up ammunition production capacity to 2 million shells per year by the end of 2025.

Rheinmetall, one of the world's biggest producers of artillery and tank shells, in February rolled out plans to increase production of the 155mm artillery shells, a standard caliber used by NATO countries, to 1.1 million by 2027.

The firm said its order backlog grew by 43% to 40.2 billion euros in the quarter. It also confirmed its 2024 sales guidance at around 10 billion euros.

($1 = 0.9274 euros)

(Reporting by Andrey Sychev, Editing by Rachel More and Alexander Smith)

By Andrey Sychev