Minister of state for housing and planning Margaret Beckett insisted that the region - stretching 40 miles on both sides of the Thames estuary from east London into Kent and Essex - was "in a strong position to weather the current economic storm and grow in the long term".
She announced plans for a new "eco-quarter" within the Gateway in which green technologies will be developed and tested, along with up to £35 million for parks and other open spaces within the region.
Mrs Beckett will today tell the Thames Gateway Forum in east London: "The financial downturn poses new challenges for towns and communities across the country. But I believe that we have sound reasons to remain optimistic for the Gateway's long-term prospects."
Over the past year the first contracts have been awarded for the construction of a new container port, known as the London Gateway.
Day-to-day management of the Gateway will this week be taken over by the Homes and Communities Agency.
Mrs Beckett added: "Now is not the time to give up on the Gateway or start watering down our ambitions. In fact, it is more relevant today than ever before."
But Conservative regeneration spokesman Stewart Jackson said: "The Government are in denial about the mess that is Thames Gateway - ploughing on regardless with unrealistic housing plans, poor strategic leadership and project management and a woeful lack of consultation with local people and their elected representatives.
"More of the same will not deliver a better quality of life for residents in the Thames Gateway."