The US tariff plan on Chinese imports may not be imposed until early June, as a 30-day period for written public comment on the tariff list is anticipated to be extended to 60 days, an US official said, according to a report by Reuters.

"We'll go through a 60-day period where we'll give the public a chance to comment on the good and the bad things in there," US Trade Representative Robert Lighthizer said during an interview on US cable channel CNBC.

He said the list would focus mainly on the high-technology products chosen by a computer algorithm to maximize pain on Chinese exporters while minimizing cost on US local consumers.

On March 23, US President Donald Trump signed a memorandum which could impose tariffs on up to $60 billion in imports from China and instructed the USTR to publish a tariff list by April 6 and provide a 30-day period for written public comment.

Lighthizer said there would be a certain amount of tension between the US and China and there is hope tariffs could be avoided by negotiations, but it would take years to bring the US-China trading relationship back to a good place.