Transactions with associate companies stretching back years are behind much of the €12.8bn wiped off Steinhoff International’s books, and the board has warned there may be more to come.

It has also said it intends identifying and disclosing details of all the related parties.

The €12.8bn restatement is more than twice the €6bn initially estimated by the board in December 2017, following the shock resignation of former CEO Markus Jooste.

Steinhoff’s unaudited results for the six months to end-March 2018 include early details of the extensive restatement of the group’s balance sheet, which was previously bloated by related-party transactions, inflated profits and the "incorrect application of group accounting principles" under Jooste’s watch.

As a result of ongoing investigations into the related-party transactions and accounting irregularities, management was forced to impair the value of the group’s reputation, known as goodwill, and brand names, as well as restate cash assets to the tune of €10.9bn in the end-March 2017 balance sheet.

An additional €1.9bn was written off at the end-March 2018 balance sheet. The combined restatements reduced the value of the group’s assets to €19.8bn at end-March, down 44% from the €34.7bn reported in March 2017.

Former chairman Christo Wiese, who is suing Steinhoff for R59bn, told Radio 702 on Friday that the extent of the restatements was "mind-boggling" and asked how it was possible the books could have been manipulated for more than a decade.

The group, which owns global brands such as Conforama, Pep Europe, US-based Mattress Firm, UK-based Poundland and 71% of Steinhoff Africa Retail, struggled with tough trading conditions during the review period.

Despite the challenges, the board said it had made progress with its creditors and had reached agreement on key terms for a restructuring plan with third-party creditors.

In the six months to end-March 2018 turnover was down 6% to €9.3bn from €9.9bn.

Excluding certain one-off items, the group managed to achieve earnings before interest, tax, depreciation and amortisation of €340m, down 16% from €405m in the six months to end-March 2017.

The six-month review period was negatively affected by the crisis at the holding company level as third-party funding became tighter and customers were affected by the negative media. In addition, management had to contend with low economic growth rates, increased competition and increased customer indebtedness.

The first set of figures released by Steinhoff since the December 5 revelation of accounting irregularities and the resignation of Jooste come with a warning that they should be used with caution.

In a note accompanying the results, management said the restatements of the asset values were based on its best estimate of the value based on the available information. The figures were management’s best estimate to date.

"It has emerged that the overstatement of profits, transactions that were not at arms’ length, impairment of loans, together with increased discount rates applied in valuing goodwill and brands resulting from increased risk profiles, has resulted in material additional impairments of goodwill, intangible and other assets," the board said.

The underlying transactions that have led to the massive restatements are still being investigated by management, which is hoping to know the full extent of the required restatements by December 2018.

"Management’s focus is to ensure that all related parties and non-arms’ length transactions are identified and correctly accounted for in the accounting records," the management board said.

It said it wanted to ensure that all related parties "are identified and appropriately recognised and disclosed".