Washington is planning another tidal wave of tariffs on Chinese imports that represent a worst-case scenario for markets and major industries on both sides of the Pacific.

Seven days of public hearings were due to begin on Monday as major businesses issue their loudest warnings yet about layoffs, lost business and the US’ waning industrial predominance.

Some industries, such as steel and aluminium producers, have benefitted from US President Donald Trump’s trade policies and strongly support tariffs.

But the lion’s share so far are pleading with his administration to spare the imports they depend on – if not to step back from the brink of an unprecedented all-out trade conflict that economists say would prove dire for global growth.

Should they take effect, the newest $300 billion round of tariffs – which follow last month’s sudden crack-up in trade negotiations with Beijing – would mean stinging duties cover just about all of the more than half trillion dollars in goods that Americans buy from China every year.

Major trade bodies share Trump’s principle grievances with Beijing, accusing it of rampant industrial espionage and massive state intervention in markets.

But in a letter to Trump on Thursday, hundreds of US companies large and small, including retail giants Target and Walmart, warned Trump the new tariff round could cost two million jobs and cut US GDP growth by a full percentage point.

So far, Trump has imposed tariffs on more than $250 billion in Chinese goods but this has spared most consumer items from major price increases.

Still, William Reinsch, a trade policy expert at the Center for Strategic and International Studies, said the new tariffs were likely to pinch ordinary consumers far more.

“Unlike the previous times, I think there’ll be a sharp negative reaction from the public,” he said.

“If these things go into effect in July, what you’re going to see is fairly immediate price increases on a whole bunch of things right at the point where people are gearing up to shop for the fall season, for winter clothes and for Christmas.”

Trump has pinned hopes for resolving the impasse on a planned meeting with his Chinese counterpart Xi Jinping later this month at the Group of 20 summit in Japan.