Shoppers in the UK are expected to spend nearly £1.3bn ($1.6bn) this Black Friday in record-breaking sales.

Interactive Media in Retail Group (IMRG), UK's industry association for e-retail, has forecast that £1.27bn would be spent this Black Friday, a 16% rise over last year. The association expects a total of £6.77bn to be spent on e-tailers between 21 and 28 November – the Black Friday peak period.

About 51% of the total online shopping is expected to be completed on smartphones and tablets.

"Black Friday as an event has shown a remarkable capacity for evolving each year and it seems set to change further this year," Justin Opie, managing director at IMRG said in statement.

"The 'Black Friday peak period' started out as a single day of discounting activity, which then became a weekend (in 2014), an extended period (in 2015) and now looks set to span an entire week on average – during which time we anticipate that a high volume of pre-Christmas sales will be made," he said.

The Black Friday trend built up momentum between 2010 and 2013. The following year, it became a huge event in the UK, overtaking Cyber Monday. Last year, some retailers launched campaigns on the eve of Black Friday, extending the peak period with several activities between 26 and 30 November.

Retailers across the country are offering big discounts this year and some on high street, including Tesco, Argos, Currys PC World and Amazon are offering more discounts. Tesco, in particular, is opening its largest stores at 5am.

Paul Martin, the UK head of retail at KPMG told the Guardian that traditional Christmas shopping period had been distorted by Black Friday.

"For retailers it has always been questionable whether Black Friday really benefits them in the long run, and in the current environment of rising costs and squeezed margins – perhaps it's even more so. This year some retailers have decided not to partake, while others have spread their offers out over a longer period in order to ease pressure on logistics and IT infrastructure," said Martin.

The surge in Black Friday sales puts a strain on websites and parcel delivery services. In 2015, websites of Argos, Tesco, John Lewis and Boots crashed due to the huge volume of incoming traffic. This year, experts believe that carriers might face difficulty in delivering products on time.

Dino Rocos, operations director at John Lewis had said that last year the Black Friday week had attracted the highest sales and their website experienced a 300% rise in traffic in early hours of Friday. "We are well prepared for the demand but it's our customers who will decide the exact pattern of trading," Rocos said.