With no sign of peace or a ceasefire on the horizon nearly six months after Russia's invasion began, holders of around 75 per cent of the outstanding total agreed to Kyiv's proposal, documents showed on Wednesday.

"Ukraine will save almost $US6 billion ($A8.5 billion) on payments," said Prime Minister Denys Shmyhal in a statement. "These funds will help us maintain macrofinancial stability, strengthen the sustainability of the Ukrainian economy and improve the power of our army."

The solicitation needed approval by holders of at least two-thirds of the total and more than 50 per cent of each issue.

"The two-year debt freeze makes sense because even if the war ends soon, Ukraine's situation is not going to improve overnight," said Stuart Culverhouse, chief economist at London-based research firm Tellimer. "Creditors were even surprised that the country decided to be current on the bonds until now."

BlackRock Inc, Fidelity International, Amia Capital and Gemsstock Ltd are among the biggest holders of Ukraine's debt, whose market value has slumped by more than 80 per cent since a build-up of Russian troops on its borders began late in 2021.

A separate but related consent solicitation approved by creditors allows changes to about $US2.6 billion ($A3.7 billion) of GDP warrants, a derivative security that triggers payments linked to a country's gross domestic product.

Creditors of Ukravtodor and Ukrenergo, two state-owned firms that have government guarantees on their debt, have approved separate solicitations similar to the one proposed by the sovereign.

With Ukraine facing an estimated economic contraction of as much as 45 per cent in 2022, bilateral creditors including the United States, Britain and Japan had also backed a debt repayment delay and a group of governments in the Paris Club agreed to suspend payments until the end of 2023.

Australian Associated Press