The auditor of Crocs Inc has expressed "substantial doubt" about the plastic clog maker's ability to continue as a going concern, it emerged today (18 March).

The comments from accountant Deloitte & Touche were included in Crocs' annual report, which was filed with the Securities and Exchange Commission on Tuesday.

At the end of its financial year on 31 December, the company said it had $51.6m in cash and $22.4m in borrowings under a credit facility that expires on 2 April.

It is currently in talks to extend the credit facility and is negotiating with financial institutions to obtain an asset backed lending arrangement.

Crocs may also explore other sources for capital to meet ongoing needs, it said.

In its results for the year Crocs swung to a net loss of $183.6m, from a profit of $168.2m the year before.

The shoe maker was hit by a 15% drop in sales, as well as charges of $145.2m for foreign exchange rate losses, the shuttering of production sites in Brazil and in Canada, and inventory write-downs.

In its defence, the company today said it intends to continue its cost cutting actions throughout 2009.

It also said it had generated positive cash flows from operating activities for each of the last three years.