The announcement comes in the wake of the developer submitting a planning application for its Heron Plaza development, adjacent to the Heron Tower site.
It is hoped that the 183m-high landmark will be completed by 2008.
The announcement came at the company's annual lunch, hosted last week at London's Savoy hotel. The tower scheme has been on the back-burner due to Heron's own caution regarding a previously stagnating City office market.
Heron Plaza, submitted for planning in February, involves a new 24-storey development on the site of Staple Hall in Houndsditch. Another adjacent building, Stone House, will be rebuilt and extended, with a new atrium and a retail arcade running through it.
The total value of Heron's plans for the site is thought to be in the region of
£800 million. The company has an £800 million property portfolio, with assets in France, Spain, Sweden, Italy and Britain.