Speaking in an interview with a Japanese newspaper, Mr Zelensky said he needed more tanks and rocket launchers before sending troops to the frontlines.
In an interview with Yomiuri Shimbun, Mr Zelensky said the situation in eastern Ukraine was “not good”, due to a lack of ammunition.
“We are waiting for ammunition to arrive from our partners," he said.
Asked when an expected counter-offensive could begin, he said: “We can’t start yet, we can’t send our brave soldiers to the front line without tanks, artillery and long-range rockets."
He added: “If you have the political will, you can find a way to help us. We are at war and can’t wait.”
However, British officials said Friday that the Russian assault on Bakhmut has stalled as its military has suffered a large number of casualties.
In its latest intelligence update, the UK’s Ministry of Defence (MoD) said Russia’s situation has likely been worsened by “tensions between the Russian ministry of defence and Wagner Group, both of whom contribute troops in the sector”.
The MoD said Russia had instead shifted its operational focus towards Avdiivka, south of Bakhmut, and to the Kremina-Svatove sector in the north – “areas where Russia likely only aspires to stabilise its frontline”.
They added: “This suggests an overall return to a more defensive operational design after inconclusive results from its attempts to conduct a general offensive since January 2023.”
Ukraine’s allies have promised more tanks and longer-range missile systems, but Ukraine has pushed for these to be delivered as quickly as possible amid the planned counter-offensive.
Ukrainian commanders have hinted it might be soon, with Oleksandr Syrskyi, commander of Ukraine’s ground forces, suggesting this week it will be “very soon".
US defence officials said earlier this month that “Ukraine doesn’t have any time to waste” on the counter-offensive.
“We have to deliver swiftly and fully on our promised commitments,” US Defence Secretary Lloyd Austin said.
“That includes delivering our armoured capabilities to the battlefield and ensuring that Ukrainian soldiers get the training, spare parts, and maintenance support they need to use these new systems as soon as possible.”