The increased investment will see Film4's yearly spend on film development and financing grow to £10 million, returning it to pre-downturn levels.
The budget increase also follows last month's passing of the Digital Economy Act, which included Channel 4's commitment to back UK-produced film projects as part of its new public service remit.
Speaking yesterday at a pre-Cannes reception, incoming Channel 4 chief executive David Abraham said: "Film4 embodies all that's great about Channel 4's place in our creative culture.
"For 28 years it has played a distinctive role in the British film industry and we are delighted that this has now been formally acknowledged in the update to Channel 4's remit contained in the Digital Economy Act.
"Under my watch investment in British film will continue to sit at the heart of Channel 4's public service mission."
Film4 controller Tessa Ross added: "Film has always been in the DNA of Channel 4, but this added protection, through the extended remit, comes at a time when this significant part of our British culture is in particular need of protection.
"To be able to commit an extra £2m each year to filmmakers and to work that we care about gives us all great hope for the future."
Film4 currently has two new films - Mike Leigh's Another Year and Hideo Nakata's Chatroom - in the official selection at this year's Cannes film festival.
The Film4-backed Four Lions, directed by Chris Morris, is also scheduled for release in the UK this week.
It was recently announced that a high definition version of the Film4 channel will launch exclusively on Virgin Media in the summer.