BUENOS AIRES (Reuters) - Argentina’s black market peso and its official currency both hit new lows on Thursday ahead of the country’s long-anticipated offer to creditors for restructuring about $70 billion in debt.

FILE PHOTO: Argentine one hundred peso bills are displayed in this picture illustration taken September 3, 2019. REUTERS/Agustin Marcarian/Illustration

Latin America’s third largest economy is set to make its proposal to international creditors later on Thursday in order to push back payments on bonds issued under foreign law.

With the proposal already delayed from Argentina’s target date of March 31 due to the coronavirus pandemic, bondholders said they are preparing for steep losses amid a lack of information from the government.

Traders said the black market peso fell to 100 per U.S. dollar, a historic low which marked a 15% loss since March 19.

Argentina's official peso ARS=RASL was 0.18% weaker at 65.74 per U.S. dollar, also hitting a new low. Country risk rose 37 basis points to 4,031, according to the JP Morgan Emerging Markets Bond Index Plus 11emj.

Meanwhile, Argentina's over-the-counter bonds RPLATC rose 0.6% on speculative buying of stocks and bonds, traders said.

The government has told its creditors the country will need substantial debt relief and that any offer will have to be sustainable, even as the pandemic underscores the prospect of a deep recession for the country this year.

Investors have said they expect haircuts and coupon reductions in Argentina’s initial offer, though the proposal could be just a first step in a lengthy negotiation process.

Nikhil Sanghani, a London-based economist at Capital Economics, said analysts will be watching the offer closely for signs of debt sustainability.

“We think that Argentina needs debt relief of around $85 billion to $100 billion, as opposed to the International Monetary Fund’s estimate of $50 billion to $85 billion, to return its public debt to a sustainable level,” Sanghani said.

Argentina agreed to a $57 billion financing package with the IMF in 2018, the largest in the fund’s history.

In a videoconference with IMF officials on Thursday, Argentine Economy Minister Martin Guzman endorsed efforts by the fund and World Bank to suspend debt service payments by the poorest countries and urged the private sector to take on a more active role.

“Debt sustainability will be critical to the economic recovery of the affected countries. Therefore, efforts in this regard must be comprehensive and include the private sector,” Guzman said, according to a ministry press release.