RMJM is the only British-based firm still in the running to win the much-criticised contest, alongside some of the world's biggest architects, such as Rem Koolhaas, Jean Nouvel and Daniel Libeskind.
Other names on the shortlist are Herzog & De Meuron and Massimiliano Fuksas.
However, pressure is mounting on the entrants from a growing number of top-level opponents to the massive £324 million office scheme including, it has emerged today, the head of the city's famous Hermitage museum.
It is reported that Hermitage director Mikhail Piotrovsky has blasted all the competition entries - all of which feature enormous skyscrapers - because of the potential impact on the historic city, which was once Russia's imperial capital.
A former head of the city's architectural protection committee, Nikita Yaveyn, has also come out against the schemes saying that if any of them were ever realised the 'only solution [would] be to call in terrorists to blow it up'.
The latest clamour is not the first controversy to hit the project. Earlier in the year the Richard Rogers Partnership decided to drop out of the contest even though the practice had made it into the final seven.
The winner will eventually get their hands on designing a 300,000m 2commercial complex, including a 300m-tall office tower, next to the city's famous Bolsheokhtinsky Bridge.