The New York Times is moving part of its Hong Kong bureau to Seoul, amid growing concern about the impact of new national security laws on the freedom and safety of the press.

The US outlet will relocate its digital team – about one-third of its current Hong Kong bureau – to the South Korean capital over the next year, it said. Correspondents and print production teams for the International New York Times, the paper’s European and Asian edition, will stay in Hong Kong.

Staff was informed of the move in a memo from editors and executives on Tuesday.

“China’s sweeping new national security law in Hong Kong has created a lot of uncertainty about what the new rules will mean to our operation and our journalism,” it said. “We feel it is prudent to make contingency plans and begin to diversify our editing staff around the region.”

A New York Times report on the relocation said some of its employees had struggled to secure work permits, which had rarely been an issue Hong Kong in the past.

“With the city facing a new era under tightened Chinese rule, Times editors determined they needed an additional base of operations in the region,” it said.

On 30 June, Beijing imposed sweeping national security laws on Hong Kong, bypassing the semi-autonomous region’s own legislature, that outlaw subversion, sedition, terrorism and collusion. However, the laws have been criticized as so broad and ill-defined that even the most benign acts supporting independence can be viewed as illegal.

The legality of journalistic practices in Hong Kong is also unclear, and inquiries to the Hong Kong government have drawn only warnings that the press will not be targeted as long as journalists abide by the new laws.

The editor of the Hong Kong Free Press, Tom Grundy, wrote in the Guardian on Tuesday the laws had been designed to have a chilling effect on media.

“The government will not give us straight answers to questions about the security law – and that is by design,” Grundy said. “Fuzziness is a feature, not a bug – the authorities want journalists to overcompensate, tip-toe around ill-defined red lines, and ultimately self-censor.”

Staff from the New York Times, the Wall Street Journal, and The Washington Post were expelled from mainland China earlier this year, amid continuing diplomatic hostilities over foreign media based in the US and China.

“Hong Kong has been a leader in supporting the rights of a free press in Asia for decades, and it is essential that it continues to do so,” New York Times spokeswoman, Ari Isaacman Bevacqua, said.