On Thursday Mumbai International Airport Pvt Ltd sent a legal notice to Vijay Mallya's Kingfisher Airlines threatening to put it on cash and carry from Saturday citing non-payment of dues.As This is with regards to the dues worth 90 crores which were not cleared by Kingfisher for the past six months.

Kingfisher Airlines will have to pay Mumbai International Airport Pvt Ltd -- owned by a consortium of investors led by infrastructure firm GVK Power -- 500,000-600,000 rupees a day to operate its daily flights from the airport, said the source adding the airline has not yet replied to the notice.

"As a matter of policy we do not comment on supplier and partner relationships," Prakash Mirpuri, vice-president, corporate communications, Kingfisher, said in a statement.

It said its flights will operate "normal", as per its revised schedule put on the company's web site.

Kingfisher, which has never made a profit since its launch in 2005, is facing series of financial difficulties. It has eroded its net worth after reporting a doubling of its loss in the fiscal second quarter on higher fuel prices and operating costs.

The airline has been asked by its creditors to raise $160 million in equity while holding debt restructuring till it has a credible plan. On November 24, AerCap Holdings NV, one of its aircraft lessors, said it would take back two of its aircraft in coming months on disagreement over extension terms.

Many Indian carriers including state-run Air India are troubled by rising fuel costs and price wars emanating from intense competition causing investors and government to worry about their survival.

Kingfisher shares, now valued by the market at $231.15 million, closed down 1.04 percent to 23.85 rupees in a Mumbai market that rose 2.3%.