The sale was completed on Sunday (31 May) following receipt of unconditional competition clearance from the relevant authorities.

The move follows the company’s acquisition of Spanish business Andopack and its purchase of Middleton Paper's Recycling Division last autumn.

DS Smith group chief executive Miles Roberts said the venture will strengthen the company's capabilities and enable it to access customers in new regions.

He said Duropack is a business that “is highly complementary to DS Smith’s geographic footprint and transforms our position in higher-growth south-eastern European geographies.”

He added: “We look forward to integrating the business into the DS Smith Group and are excited about the excellent opportunities for customers, employees and shareholders.”

DS Smith had initially proposed the acquisition of Duropack for approximately €300m (£218m) in February.

At the time Roberts had said: “Like DS Smith, Duropack is also a very strong business, with outstanding market positions throughout south-eastern Europe. It employs just under 3,000 people and has a breadth of offer that covers packaging and recycled paper as well as recycling capabilities.”

Duropack has 14 corrugated packaging sites, two paper mills and 18 recycling sites across nine countries; Austria, Hungary, Bosnia, Bulgaria, Macedonia, Serbia, Slovakia, Croatia and Slovenia.

The firm had gross assets of €281m (£204m) as of 31 December 2014, and EBITDA of €41m (£29m) in 2014.

In its trading update for the year to 30 April 2015, which was released last month, DS Smith said it was trading in line with expectations, with its strong underlying growth offsetting the continued strength of sterling.

The group’s full financial results for the year to 30 April 2015 will be released on 25 June.