The publisher has been hit by a 15 percent tariff, introduced by US President Donald Trump's administration against products made in China, including Bloomsbury's books that are printed there.
"It is not a cost we anticipated, and it's one we hope to take in our stride," Newton told BBC broadcasting network.
He also expressed hope that tariffs will not have a strong effect on 2019 financial results. The publishing house has reported a five percent decrease in profit from March to August.
US has been waging a tariff war against China for almost a year now, while Beijing has retaliated with its own tariffs on US goods. The ongoing tensions have affected the trade internationally, with the global growth having dropped up to 0.6%.