Indonesian Defence Minister Prabowo Subianto pitched the idea at the Shangri-La Dialogue defence summit in Singapore where he was a speaker.

The plan included an "immediate cessation of hostilities", a ceasefire "at present positions", and demilitarised zones that would be guaranteed by observers and United Nations peacekeeping forces.

He also suggested an eventual "referendum in the disputed areas" organised by the UN.

But Ukrainian Defence Minister Oleksii Reznikov, who was attending the two-day summit, flatly rejected the proposal.

"It sounds like a Russian plan, not Indonesian plan," he said. "We don't need this mediator coming to us (with) this strange plan."

China has presented its own peace plan to end the war -- a vague list of proposals to which European Union politicians have reacted with scepticism.

While Beijing says it is a neutral party to the conflict, it has been criticised for refusing to condemn Moscow's invasion.

In contrast, the United States and Western allies have delivered billions of dollars in weapons and other aid to Ukraine since Russia's invasion.

Jakarta, which favours non-aligned diplomacy, had previously attempted to mediate peace.

Indonesian President Joko Widodo travelled to Kyiv and Moscow and met the nations' leaders last year, while his country chaired the G20 bloc of major economies.

Subianto's proposal was also criticised at the summit on Saturday by EU foreign policy chief Josep Borrell.

"We need to bring peace to Ukraine", but it must be a "just peace, not a peace of surrender," Borrell said, commenting on the Indonesian proposal.

Indonesia voted in favour of a UN resolution condemning Russia's invasion of Ukraine, but it has not applied economic sanctions against Moscow.