Germany is planning to boost its military aid spending for Ukraine, a member of the parliamentary budget committee told AFP on Tuesday.

Some 12 billion euros ($12.9 billion) more in spending is due to be approved by the committee, with the funds to go towards military help for Kyiv as well as replenishing stocks of equipment already sent to Ukraine.

The German army, or Bundeswehr, will be able to begin spending the cash this year, with further funds also earmarked for the coming years.

It was unclear how the sum would be allocated as well as the precise time frame covered by the spending.

The sum would dwarf the three billion euros spent so far by Berlin on military aid for Kyiv.

The committee will specifically vote on Wednesday on replenishing stocks of Panzerhaubitze 2000s sent to Ukraine, the source said.

Together with the Netherlands, Germany has sent 14 of the self-propelled howitzers to Ukraine, according to Berlin.

Germany has also sent 18 advanced Leopard tanks and about 40 Marder infantry fighting vehicles to Ukraine, as well as an air defence system.

The finance ministry called the extra spending "objectively indispensable" in a letter asking the budget committee to release the sum, according to Der Spiegel magazine.

Without continued support, there would be "a serious danger that Ukraine would lose its defensive struggle against the Russian aggressor, with unforeseeable consequences for the European peace order", it said.