In a one-sentence notice on its website on Monday, the Chinese Foreign Ministry said Premier Li Qiang would represent China at the G20 summit in New Delhi later this week.
The apparent snub appeared to confirm earlier reports that President Xi Jinping will not attend.
It comes with Beijing facing Western pressure on Beijing over its stance on Russia's war in Ukraine and amid worsening relations between India and China.
What China is saying
"At the invitation of the government of the Republic of India, Premier of the State Council Li Qiang will attend the 18th G20 Summit to be held in New Delhi, India on September 9 and 10," the online statement from the foreign ministry in Beijing said.
Most G20 leaders are set to attend the two-day gathering in New Delhi, starting on Saturday, although Russia has already said its President Vladimir Putin will not be there.
"The G20 is the main forum for international economic cooperation and China has always placed great importance on and proactively taken part in such events," Chinese foreign ministry spokesperson Mao Ning told a press conference when asked why Xi would not attend.
While Mao declined to directly confirm that Li's attendance meant that Xi would not go, she did not correct the assertion when it was made by reporters.
Xi has attended every G20 summit since coming to power except one Rome in 2021, amid the COVID-19 pandemic, when he joined by video link.
Media reports have circulated that Xi would skip the event for the past week, but China had remained silent on the issue.
Moment in spotlight for India
The summit has been touted as an important showcase for India, which overtook China as the world's most populous nation in April this year.
Both regional giants are rivals in technology, space exploration, and global trade. India's huge market and potential as a source for global supply chain diversification make it an alternative regional partner to China.
Bilateral relations have also soured in recent years after a flare-up in tensions on the two countries' shared Himalayan border. Clashes on the disputed frontier in 2020 resulted in 24 deaths of soldiers.
Xi held rare face-to-face talks with Indian Prime Minister Narendra Modi on the sidelines of the BRICS summit in South Africa last month, but tensions are still high.
Relations with the US have also been strained in recent years, with US President Joe Biden retaining his predecessor Donald Trump's hard line on Beijing. However, Washington has been working to restore a more effective working relationship, sending a series of senior officials to China in recent months.
Biden has said he would be "disappointed" to see Xi miss the gathering.
China has long campaigned to widen and strengthen the BRICS group of emerging economies as a counterweight to the dominance of G7 group of powerful democracies. Beijing has long faced criticism from G7 and EU members over technology, trade, human rights, and other issues.
European officials have previously said they hoped the G20 summit in New Delhi would be a chance to lobby powers like India and China to criticize their fellow BRICS member Russia over Moscow's invasion of Ukraine.
A spokesman for the German government on Monday said it regretted the decision of Chinese President Xi Jinping not to attend.
