Norwegian rig firm Songa Offshore will issue new debt and shares worth up to $150 million and convert existing bonds of the same amount to equity as part of a plan to fix a liquidity shortfall, the company said in a statement on Tuesday.

Songa's top customer, oil major Statoil, has meanwhile cut the contract length of two drilling rigs, the first by about one year and the second by six months, but still leaving Songa with an order backlog of $5.1 billion, it added.

The refinancing plan includes an immediate bridge loan of $91.5 million to safeguard operations and fix a liquidity shortfall triggered by lower than expected utilisation of rigs, delayed deliveries and other cash requirements.

Several bond and loan maturities will also be extended as part of the plan, and top owner Frederik Wilhelm Mohn's Perestroika investment firm, which holds 49.44 percent of the shares, has backed the scheme, Songa added.

"The transaction is supported by the required majority in all bonds and secured bank facilities," the firm said. "Songa Offshore is expected to be fully financed following the refinancing."

Both the debt conversion, at a price of 0.176 Norwegian crowns per share, and the issue of up to $25 million in new shares at 0.15 crowns each, will take place at a deep discount to Monday's close of 0.76 per share.

ABG Sundal Collier and Swedbank are advising on the restructuring, Songa said.

Reporting by Terje Solsvik