MOTT MACDONALD has scaled down design work on a major water supply project for the Turkish government because it has not been paid since November 2002.
The consultant and Jacobs Gibb have cut design work to a minimum on the US$1.3bn Melen water transfer scheme.
They are believed to be owed hundreds of thousands of pounds in unpaid fees.
The project is funded by the Japanese Overseas Economic Co-operation Fund and involves the construction of pumping stations, pipelines, dams and tunnels to transfer water into Istanbul from the Greater Melen Stream 150km away.
Mott MacDonald has a US$2.4M design and construction supervision contract for 4m diameter tunnels under the Bosphorus strait.
Jacobs Gibb has a design and supervision contract for pipeline construction.
No payments have been received by the consultants since the Justice & Development (AK) Party was elected to power last November. It says it is investigating claims that contracts on some government backed schemes had been awarded unfairly by the previous administration.
The Melen consultants are not under investigation but AK has yet to indicate when or if payments will restart.
Mott MacDonald has asked the Japanese government to put pressure on AK to resolve the issue, according to Melen project manager Chris Bambridge.
Bambridge said that Mott was unwilling to walk off the project because it would risk forfeiting a performance bond which it had put up.