The Financial Times reported on Wednesday that the government was monitoring the company.
"We continue to have constructive discussions with lenders over longer-term funding. We are keeping the Cabinet Office closely appraised of our progress as would be expected," an Interserve spokesman said in a statement.
"Last week we announced that we expect our 2017 performance to be in-line with expectations outlined in October... This remains the case and we expect our 2018 operating profit to be ahead of current market expectations."
(Reporting by Alistair Smout; editing by Guy Faulconbridge)