A costly slump in Chinese visitors to the US is being blamed on president Donald Trump’s tit-for-tat trade war with China.

Year-on-year figures to August show a drop of 8.4%, falling further as new rounds of tariffs against China have been announced.

The biggest impact is on bookings for group travel from China to the US, currently behind for the rest of 2018 by 34.4% compared to last year. Bookings by independent travellers down 3.9%, with leisure travel being worse affected than travel for business or travel to visit friends and relatives.

Weekly bookings from China to the US were up 2% from the last week of February – after the Chinese New Year holiday – to March 23 when Trump’s first tariffs took effect.

The negative impact on the Chinese currency, which has fallen 7.5% against the dollar since tariffs were introduced – meaning tourists’ money buys less – and warnings from Beijing about US travel security risks, have likely further influenced the trend.

Data from ForwardKeys, which predicts future travel patterns by analysing 17 million booking transactions a day, reveals that Chinese outbound bookings to the US for the rest of the year are 9.6% behind where they were at the same time last year.

However, Chinese outbound bookings worldwide are ahead by 5.5%.

This pattern of growth worldwide but slowdown to the US is consistent in every month except October.

By contrast, Chinese bookings for travel to Canada were up 4.8% to the end of July and are ahead 8% for August to December.

ForwardKeys CEO and co-founder, Olivier Jager, said: “Our findings strongly suggest that President Trump’s trade war has had a significant impact on Chinese tourism to the US.

“Looking at the year to date, we see a setback in Chinese tourism arrivals of just under 5%. If that continues to the end of the year, we estimate that the cost to the US economy will be north of half a billion dollars in 2018.

“Chinese spending in this sector is significant – it amounts to the largest category of US services exports to China. It is unquestionable that the Chinese appetite for visiting the USA is diminishing, and that is bound to worry the US travel industry.”

The United Nations World Tourism Organisation puts total spending by Chinese tourists abroad at $258 billion in 2017.

The World Travel & Tourism Council reports that the value of tourism to the US from all international visitors amounted to $200.7 billion in 2017, 8.6% of total exports.