Citigate was not invited to take part in the account review, which saw three agencies pitch for the work.
lastminute.com handed the City PR brief to rival agency Hudson Sandler, which started work on the account this week.
Hudson Sandler CEO Alistair Mackinnon-Musson said: 'They're going to review the financial and corporate positioning and there may be a change of strategy in communications, although it's too early to say what it will be.'
lastminute.com denied speculation in last week's Daily Telegraph diary that the decision to repitch stemmed from an unfavourable profile interview of co-founder Martha Lane Fox, published in The Independent last month.
But lastminute.com chief financial officer David Howell said. 'We look at all our professional advisers on a regular basis - we recently changed lawyers and felt it was time to have a change in financial PR.'
Citigate director Tony Carlisle said: 'We have had a fantastic relationship with lastminute.com and are very proud of what we achieved.'