Further job cuts are to be made at United Continental after the carrier reported a $620 million net loss for the fourth quarter of 2012.

A 6% reduction in administrative and management staff is planned from next month – amounting to 600 posts – on top of a previously announced 7% cut in senior posts.

Superstorm Sandy reduced fourth quarter revenue by $140 million and profit by $85 million.

Chief executive Jeff Smisek said: “We need to generate better unit revenue and operate more efficiently, and we are taking actions to address both of those areas.”

The fourth-quarter loss compared with a $138 million net loss for the same period in 2011. It came on revenue down 2.5% to $8.7 billion.

The full-year net loss of $723 million compared with $840 million net income for 2011, was struck on operating revenue up 0.1% to $37.2 billion.

The fourth-quarter losses were deepened by $439 million in special charges, mainly $408 million for post-merger integration, up from $170 million a year earlier.

Special charges for the full year were $1.32 billion, including $739 million of integration costs.

Chief financial officer John Rainey said the results “clearly fell short of our expectations and the return goals we have set”’

He added: “2013 will be an important year for us as we take the necessary steps to create economic value and achieve a sufficient level of profitability.”