The government has suspended funding on a project aimed at improving transport links in the Thames Gateway.
Chief Secretary to the Treasury Danny Alexander said its £23m contribution to the £200m Kent Thameside Strategic Transport plan was being put on hold.
A government spokesman said it needed to look carefully at spending.
Kevin Lynes, chairman of the Kent Thameside Regeneration Partnership, said they would continue to press for the scheme to go ahead.
The Thames Gateway area stretches from east London into Kent and Essex.
The £200m transport programme aims to improve road junctions and bus transit schemes on the A2 to accompany housing and commercial developments.
Mr Lynes said: "Quite rightly, the new coalition government is taking stock and reviewing its capital spending programme.
"The county council and its partners in Kent Thameside will continue to press for the necessary transport schemes to go ahead."
He added: "Our task now is to ensure that this partnership continues to drive through efficiencies, ensuring that every penny invested results in improved outcomes for this area."
A breakdown of the total funding for the transport programme includes £72m from the Department of Transport, £40m from Land Securities, £60m from private sector sources and the £23m which the treasury put on hold.
'Good for UK'
A Communities and Local Government spokesman said: "The Thames Gateway is vital to supporting growth in London and the South East and the government remains committed to its future by giving councils more freedoms to decide how they run the Gateway.
"We are in a difficult economic situation and we have to look carefully at past spending and consider what we do differently in future."
Former Labour Lord Chancellor Lord Falconer urged the government to recognise the importance of long-term investments such as the Thames Gateway.
He said: "By any objective measure, investment in the London Thames Gateway is good for the UK economy, such is its strategic importance.
"Of course there are economic challenges ahead, but in the Gateway we also have fantastic opportunities."