Russia's invasion of Ukraine and a global food crisis aggravated by the war will be the focus of world leaders when they convene at the United Nations in New York this week, a gathering that is unlikely to yield any progress toward ending the conflict.

"It would be naive to think that we are close to the possibility of a peace deal," said UN Secretary-General Antonio Guterres ahead of the high-level meeting of the UN General Assembly.

Geopolitical divides hardened by the seven-month-old war are likely to be on full display as the United States and Western allies compete with Russia for diplomatic influence. US Ambassador to the United Nations, Linda Thomas-Greenfield, said, "other countries have expressed the concern that ... as we focus on Ukraine, we are not paying attention to what is happening in other crises around the world."

"That is not the case," she told reporters.

Guterres said the geopolitical rifts, "are paralyzing the global response to the dramatic challenges we face."

Russia and Ukraine are major grain and fertilizer exporters and the United Nations has blamed the war for worsening the food crisis that was already fueled by climate change and the Covid-19 pandemic.

The United States is due to co-host a food security summit with the European Union and the African Union on the sidelines of the UN gathering, along with a Covid-19 global action plan ministerial meeting and a replenishment conference for the Global Fund to Fight AIDS, Tuberculosis and Malaria.

"Underlying a lot of these meetings will be a huge amount of tension between Western countries and representatives of the global south in particular," said Richard Gowan, UN director at the International Crisis Group. "There's still a lot of ill feeling over issues such as the Covid vaccine rollout, climate financing ... and now food prices. All these issues are driving major wedges among UN member states."

French President Emmanuel Macron intends to use his two-day visit to New York to lobby countries that have remained neutral in the war to try and bring them onside with the West, French officials said.

The General Assembly agreed on Friday to allow Ukrainian President Volodymyr Zelensky send a pre-recorded video statement, while the Ukrainian Foreign Minister, Dmytro Kuleba, will attend a UN Security Council ministerial meeting on Thursday in Ukraine, along with US counterpart Antony Blinken, Russia's Sergei Lavrov and China's Foreign Minister Wang Yi.

World leaders will convene in New York this week. AP

Focus on war, food crisis at UN gathering