News of interim loss comes a day after newspapers link Minerva to the Labour loans row.
Minerva has blamed a decision to pursue developments rather than short-term investments for a loss of £2.1m in the six months to December 2005.
The property firm, which is developing the Walbrook in the City of London as well as Park Place shopping centre in Croydon, revealed the pre-tax loss this morning. It compares to a £1.9m pre-tax profit in the same period of 2004.
Minerva is also planning a luxury residential redevelopment of the Odeon cinema at High Street Kensington.
Salmaan Hasan, chief executive of Minerva, said: "We are focused on driving value for our shareholders from existing and new development opportunities which now encompass central London offices, a prime shopping centre and premium residential"
The company's results come the day after The Sunday Times linked two Minerva chairmen to the Labour loans row.
The paper reported that John Prescott had handed planning permissions to two Minerva schemes in the months following loans to the Labour party from current chairman Andrew Rosenfeld and former chairman Sir David Garrard.