Australian raw black tiger prawn at 139.90 yuan a kilogram and Atlantic salmon fillet for 199.90 yuan a kilogram, as well as 12 butter croissants for 47.90 yuan, were also popular with shoppers.

Among the items sold out within minutes after the branch opened at 9am were sets of Samsonite luggage and the large-size purplish-pink stuffed Disney teddy bear Lotso.

Day-to-day necessities such as two 3.25-litre bottles of liquid detergent for 59.90 yuan and clothing, including a set of three Calvin Klein men’s boxer shorts for 125.90 yuan were also popular.

The store on Saturday was not as packed as it had been a day earlier.

There were no long queues outside the store before opening time, but there were still hundreds of people waiting in zigzag queues in part of the multistorey car park above the shop floor.

A security guard said some of the car park had been pressed into service to cope with the large numbers of shoppers on a temporary basis for a few days after the opening.

But the queues moved smoothly and it took about 15 minutes for shoppers to get into the store early in the day. But more people arrived in droves at noon, which led to half-an-hour waiting times for entry.

Hongkongers queue for more than 2 hours as they flock to new Shenzhen Costco

Hongkonger Hugo Chow and his wife drove for about three hours and arrived at the store about opening time. The 28-year-old service adviser in the car industry said he set out early to avoid the crowds. Chow added he was keen to explore the store and explained he had previously had a pleasant shopping experience at a Costco branch in Seattle in the United States.

“I came here to explore the store as I like the livelier shopping atmosphere on the mainland compared with Hong Kong,” he said.

Chow, who said he planned to return once or twice a month, said he estimated the items would have cost double that amount in Hong Kong.

Tyler Yip travelled with his wife from their home in Kwai Tsing in the New Territories, to the store on Saturday morning.

Yip, in his 30s and who works in banking, said they earlier planned to dine in Shenzhen, so they decided to spend the morning shopping at Costco as well.

“The overall shopping experience is good, except for the large number of shoppers, but the crowds are already smaller than we expected,” he said.

The couple spent about 1,000 yuan on a pack of two Calvin Klein bras, a set of three men’s boxer shorts from the same designer as well as a box of croissants and three boxes of organic shiitake mushrooms and other goods before they called it a day about noon.

Yip said he was pleased that they had saved about 1,000 yuan on their buys compared with Hong Kong.

“We can save much money shopping here as the prices of many products are lower than those in Hong Kong,” he said.

He added he also planned to return to the store in the future for more cheap deals.

It took about two hours for Hong Kong retiree Wong Yuen-sun, 68, to travel with her husband and son from their home in Sai Kung to the Costco store on Saturday morning.

The trio bought three boxes of strawberries, a box of oats and a roast chicken, which cost about 350 yuan in total.

“The strawberries are much cheaper here and we also don’t have these brands of oats and roast chicken in Hong Kong,” she said.

She said she had shopped at Sam’s Club, another warehouse-style store in Shenzhen owned by American supermarket giant Walmart, before and reckoned Costco had a wider range of brands on offer.

Bulk buying megastores in Shenzhen may lure even more Hongkongers over border

“I’m exploring the new store and I will take my grandson and other family members and relatives next time,” she said.

The Post found that 2-litre and 630ml containers of Walch disinfectant cost a total of HK$119 (US$15.22) at Hong Kong health and beauty chain Watsons. That compared to a price of 118.60 yuan for two 2-litre containers of the same brand at Costco.

A box of three Calvin Klein men’s boxer shorts sells for HK$343 in Hong Kong, but the same item is priced at 125.90 yuan at the Shenzhen Costco.

A two-piece hard-sided set of Samsonite luggage had a price tag of 769.90 yuan at Costco. The same cases cost between HK$1,888 and HK$1,980 at Hong Kong retailers.

The Shenzhen store is Costco’s first in south China and the sixth on the mainland.

The four-storey branch, with a floor area of 44,500 square metres (478,994 sq ft), features about 4,000 brand name products sourced from Chinese and international manufacturers.

Massive members-only bulk retailers across the border have become increasingly popular among Hongkongers because of the cheap deals on offer.

The stronger Hong Kong dollar value against the yuan has also helped make shopping on the mainland more attractive.

Simon Lee Siu-po, an economist and an honorary fellow at Chinese University’s Asia-Pacific Institute of Business, explained that Hongkongers could find lower-priced items across the border because shops and mall owners did not have to take into account hefty rents and high staffing costs.

“For food and retail goods, the first [price] difference came from rental expenses, which would account for 10 per cent of the price,” Lee said.

“The other part came from salaries, which would be high in Hong Kong. These together would produce a big price difference.”

Lee added added that it would still be a bargain even though Hongkongers had higher transport expenses to shop across the border. He explained the more people bought, combined with the price gap between the two cities, would easily offset transport costs.

Additional reporting by Lilian Cheng