At a campaign launch for a Yes vote in May’s referendum, he said MPs would be denied “jobs for life” by holding safe seats if the voting system changed.
AV, where voters rank candidates rather than choose a single candidate, is also backed by comedian Eddie Izzard.
The No campaign says AV would mean some people’s votes count more than others.
Voters across the UK are being asked on 5 May whether they want to keep the current “first-past-the-post system” for electing MPs to Westminster or change to AV.
Those who oppose change say the current system generally leads to stable government and has historically reflected the will of the public in that unpopular governments have been voted out.
The Yes campaign, launched at an event in central London billed as “politician-free”, says the alternative vote would ensure MPs aimed to secure at least 50% of the votes in their constituency.
Mr Dyke, chairman of the British Film Institute, said those opposing the campaign were “old hack politicians” and had become “complacent” about their jobs.
Former independent MP Martin Bell, also a Yes supporter, said: “Let’s not have our MPs elected by a minority and then going out and preaching democracy to the rest of the world. Let’s get our own house in order.”
Mr Izzard, the comedian and Labour supporter, said the Yes to AV campaign was “pushing for civilisation”.
Yes supporter, former athlete Kriss Akabusi, who said he was a Conservative voter, said: “First past the post worked in the 19th and 20th Century, but it doesn’t work now.”
He said the reasons given by the No campaign were “poppycock”, such as the risk of a BNP candidate being elected to Parliament.
But he said even if that was the case he would be “proud” to live in this country because he wanted to know what the people wanted.
At the event several people explained why they would be voting Yes in the referendum.
Andy, a student at Swansea University, said: “I live in a safe seat. I know lots of people who are interested in politics but they don’t vote because they know their vote won’t count.”
A spokesman for the No campaign said: “At a time when people are seeing their pay frozen and the cost of living rising, why should they listen to a bunch of celebrities who are backing a plan to spend £250m scrapping our fair voting system for one that gives some people more votes than others?”
Yes campaigners dispute the costs ascribed by the No campaign to introduce AV.