Mr Brown has previously ruled out a televised showdown
Gordon Brown has said now is "not the time" to decide whether to join in a televised debate between party leaders at the next general election.
Conservative David Cameron and Liberal Democrat Nick Clegg have said they are willing to take part in the event.
The prime minister said he was "happy to do debates all the time" but the TV proposal would be discussed later.
US presidential candidates take part in several live televised debates before each election.
There have been several calls from UK opposition leaders over the years to stage a similar event, but so far none has happened.
'Time will come'
Sky News has said it will organise a televised debate in the run-up to the next general election and "empty chair" any party leader who does not turn up.
FROM THE PM PROGRAMME
Speaking during a cabinet "away-day" at the Olympic Park in east London, Mr Brown said: "I'm happy to do debates all the time, but we're not at the point of having a general election.
"When we get to that point, this will be something that we will discuss."
He added: "There will come a time for these other things but it's not now."
The prime minister has previously ruled out the idea, saying there is a weekly debate at prime minister's questions.
But Mr Cameron has said the weekly session in the Commons is "no substitute for a proper primetime studio debate".
Mr Clegg has said politicians have to find "new and different ways to engage with voters".