George Osborne has said he wants to complete the £1.3 billion "city deal" for the Cardiff Capital Region before he delivers the 2016 Budget.
The Welsh government has already pledged £580 million, with a further £120m coming from 10 local councils in south east Wales. In November, the Welsh government called on the government to match its investment in a formal submission.
Speaking to business leaders in Cardiff, the Chancellor said "let's get on with it".
He added: "This city deal can transform this city as much as the development around the bay did a generation ago. It's a deal that will secure Cardiff's bright future.
"We will support a new infrastructure fund for the Cardiff Capital Region as part of this.
"It demonstrates our ambition for the Cardiff region and I want to see the deal signed by the time of the Budget in March. So let's get on with it."
The £1.3bn fund will be used for transport and economic development projects in the area. As yet, there is no official confirmation on projects, but it is widely expected that around half of the money will be used on a metro-style transport network in south east Wales.
Leanne Wood, leader of the Plaid Cymru party, welcomed the impending news of the deal, but called on Mr Osborne to "announce he is to open a Swansea city deal and a 'rural deal' for west Wales, to spread prosperity throughout Wales".