April 29 (Reuters) - A group of Petrofac noteholders offered the struggling UK oilfield services provider a $300 million credit line on Monday to help it secure performance guarantees on some existing contracts.

The credit support -- comprising $200 million in new funds and $100 million in credit -- would mean converting a significant proportion of the group's existing debt to equity, Petrofac said, without naming the noteholders or saying how much debt it would need to convert.

The London-listed firm also delayed the publication of its full-year results to May 31.

Performance guarantees refer to a commitment to honour the terms of the deal. Petrofac has been grappling with payment delays and cost overruns at its largest unit, engineering and construction.

A delay in advance payments on new contracts has also pushed up Petrofac's debt levels, with the company mulling ways to improve its balance sheet, including the sale of non-core assets.

Petrofac also said it had received non-binding offers for its share in the PM304 Production Sharing Contract (PSC) in Malaysia, the process for which could be completed in the third quarter of this year.

The company expects to recognise an incremental loss of about $130 million in the engineering and construction unit for 2023. (Reporting by Eva Mathews in Bengaluru; Editing by Savio D'Souza)