The 500 job cuts have been made following a consultation period which began in November and have affected both back-office staff and engineers.
The cuts have been spread across the firm's 40 global offices, with up to 120 jobs going in the UK - roughly 5% of the consultant's workforce in this country.
An interim trading statement released by the consultant today revealed that since its half year results in July its order book has fallen by 5%.
"The general economic turndown particularly affecting new commercial, retail and residential developments has impacted on some of our global operations and, where appropriate, we have taken action to match our cost base with anticipated revenue particularly in the UK and to a lesser extent in the United States," says the statement.
"Dubai is seeing a recent slowdown in growth and we are redeploying our resources to other areas of the Gulf and surrounding countries. Since the half year our order book has fallen by approximately 5% but remains well in excess of £1bn driven by our continued success in winning major international projects and public sector transport and infrastructure work particularly in Sweden and the UK."
Despite today's announcement, market analysts reacted favourably, with Numis Securities claiming WSP's previously high profit margins of 6% would allow the consultant to continue paying a dividend to shareholders even if it were to see a halving in profit levels in 2009.