The presidential office said on Saturday the visit was a personal trip to celebrate Avancena’s 49th birthday.

Christopher “Bong” Go, the president’s former special assistant, later added that Duterte’s daughter had requested the visit as a gift as it was something they had regularly done as a family in the past.

“It was actually Kitty who requested her father for the trip, as a gift,” Go said. “They used to do it even when [the president] was still mayor of Davao City. The weekend getaway is for rest and recreation.”

Photos released by Go showed the family and their entourage celebrating Avancena’s birthday at what appeared to be a Chinese restaurant.

In one picture, Avancena is seen blowing out candles on a birthday cake as Duterte looks on, and in another, Kitty joins her parents for a family photo.

Duterte was spotted in fashionwear chain Uniqlo’s shop at the World Trade Centre in Causeway Bay at around 6pm on Saturday with his bodyguards.

Southern District Council member Henry Chai Man-hon took a photo of Duterte, dressed in a dark suit, as he walked around the store and surprised a female shopper who looked at the president in shock.

“On Saturday, there were few Filipino domestic helpers [around],” Chai said, when asked if any of Duterte’s compatriots spoke to him in the shop.

Chai said some other shoppers also recognised Duterte but no one greeted the president. However, he talked to shop staff about the products.

The Democratic Party councillor, who only stayed in the shop for about five minutes, said he did not know what Duterte bought.

The Philippines’ state news agency said the family arrived in Hong Kong on Friday and were due to return home on Sunday.

‘If it’s cancer, it’s cancer’: Philippine President Rodrigo Duterte hints at health problems after undergoing medical tests

Duterte’s visit came on the heels of a claim by a former senator, Francisco Tatad, that the president recently had a successful kidney transplant in a Philippine hospital.

In a speech on Thursday, Duterte, who regularly utters profanities and curses critics, blasted Tatad. “You, Tatad, you know there’s a border between press freedom and disrespect for a person,” he said. “If I see you first, you better avoid me, f*** you. I will slap you.”

However, Duterte did not categorically deny that he had undergone an operation.

This was the second time in less than five months the president was spotted in Hong Kong on an unannounced visit.

Two days before that trip, Duterte confirmed rumours he had visited a Philippine hospital in the middle of the night. But he said he merely had a colonoscopy and the tests turned out negative.

The four were sentenced for possession of 467.8 grams of methamphetamine but Democratic Party lawmaker James To Kun-sun, who has been helping the families, argued the trial was unfair and that dubious evidence was staged to save face.

The four are applying to have the same judge review their case.

In 2016, the four men accepted a job sailing a fishing boat from the Philippines to mainland China.

Then-Philippine police chief Ronald dela Rosa, who is now running for a seat in the country’s Senate, led a team of officers together with journalists to the vessel and had the men arrested.

Additional reporting by Raissa Robles