China and the US have agreed to ease restrictions on each other's journalists amid a slight relaxation of tensions between the two sides.

The official China Daily newspaper said the agreement had been reached ahead of Tuesday's virtual summit between Chinese leader Xi Jinping and US president Joe Biden.

The agreement represents a degree of progress on an issue that has long aggravated relations, but details remain to be ironed out.

Covid-19 travel restrictions and long-standing obstacles faced by foreign media within China are also factors standing in the way of a major breakthrough in media relations.

Under the agreement, the US will issue one-year multiple-entry visas to Chinese journalists and will immediately initiate a process to address "duration of status" issues, China Daily said.

China will reciprocate by granting equal treatment to US journalists once American policies take effect, and both sides will issue media visas for new applicants "based on relevant laws and regulations", the report said.

Foreign ministry spokesperson Zhao Lijian gave no information on a timeline for implementation, but called the agreement a "hard-won achievement that is in the interest of both sides and should be cherished".

"We hope that the US will keep its promise to put the relevant measures and policies in place as soon as possible and work with China to create favourable conditions for both (nations') media to continue to work and live in each other's countries," Mr Zhao said.

In a statement to The Associated Press (AP), the US state department said China had committed to issuing visas for a group of American reporters "provided they are eligible under all applicable laws and regulations".

"We will also continue issuing visas to (Chinese) journalists who are otherwise eligible for the visa under US law," the statement continued.

China also committed to increase the length of time for which US journalist visas are valid from the current 90 days to one year.

"On a reciprocal basis, we are committing to increase validity of US visas issued to PRC (People's Republic of China) journalists to one year as well," the state department statement said.

Not mentioned in either statement were press conditions in the semi-autonomous Chinese territory of Hong Kong, where both local and international media have come under increasing pressure.

The Economist said last week that Hong Kong had refused a visa renewal for its correspondent Sue-Lin Wong. Authorities have not explained why.

Limits on journalists have fuelled tensions between the two countries for more than a year after the US cut 20 visas issued to Chinese state media journalists and required those remaining to register as foreign agents, among other changes.

China responded by expelling journalists working for US outlets and severely restricting conditions for those continuing to work in the country.

The new agreement "was the result of more than a year of difficult negotiations over the treatment of media outlets in both countries", China Daily said.

"It is hoped that more good news is ahead for the two countries' media outlets through further China/US co-operation," the newspaper added.

The state department said it had "remained in close consultation with the affected outlets, as well as other outlets facing personnel shortages due to PRC government policy decisions, and we are gratified their correspondents will be able to return to the PRC to continue their important work. We welcome this progress but see it simply as initial steps."

The state department also said it would continue to work towards expanded access and better conditions for US and foreign media in China, where they face considerable obstacles ranging from questioning by police, harassment preventing them from doing their work, personal threats and lawsuits brought by people they interview.

"We will continue to advocate for media freedom as a reflection of our democratic values," the state department told the AP.