Hong Kong's top Catholic cleric, Bishop Stephen Chow, will visit Beijing in April, the first such visit in nearly 30 years.

Chow's five-day trip, to start on April 17, follows an invitation last year by the Bishop of Beijing, Joseph Li Shan, the Hong Kong Catholic Diocese said in a statement on Thursday. 

It cited Chow saying the visit "underscores the mission of the Diocese of Hong Kong to be a bridge....and promote exchanges and interactions between the two sides".

A Diocese spokesperson on Friday confirmed to Reuters that it will be the first time since 1994 - when Hong Kong was still a British colony - that a Hong Kong bishop has officially visited Beijing.

Chinese foreign ministry spokeswoman Mao Ning said that China was not aware of Chow's upcoming visit.

Hong Kong has for decades been a strong Catholic beachhead on the edge of a mainland China under officially atheist Communist Party rule, and is seen by some Catholics as a source of friction in a habitually tense Sino-Vatican relationship.

Vatican officials say Hong Kong is not part of a secret but provisional 2018 agreement between the Holy See and Beijing over the appointment of bishops.

That accord was a bid to ease a longstanding divide across mainland China between an underground flock loyal to the pope and a state-backed official church. For the first time since the 1950s, both sides recognised the pope as supreme leader of the Catholic Church.

Some local priests and missionaries, however, fear that Beijing has been trying to tighten its control over Hong Kong Catholics, in part because of the deal, extended in October for a further two years.  

Pope Francis named Chow as bishop of Hong Kong in May, 2021 -- a long-delayed appointment amid growing Western concern over human rights and freedoms in the city.

Cardinal Joseph Zen, one of Chow's predecessors and a prominent critic of the Sino-Vatican deal, was found guilty in November for failing to register a now-disbanded fund for democracy protesters. He was fined HK$4,000 ($512).