Mr Straw was Mr Brown's leadership campaign manager
"In hindsight" Gordon Brown should have called a general election in the autumn of 2007, Jack Straw has said.
But the justice secretary told the New Statesman he had not been among those pushing for an election at the time.
He said evidence suggested Labour would not win with a good majority and voters did not like unnecessary elections.
Mr Brown enjoyed an opinion poll bounce after taking over as PM but amid much speculation was accused of "bottling" a decision on a snap election.
The Conservatives have since enjoyed a lead in the opinion polls and Labour ministers have described themselves as the "underdogs" in the upcoming general election - which must be called by June 2010.
Clocks went back
Mr Straw was the campaign manager for Mr Brown's leadership bid - he eventually stood unopposed - after Tony Blair announced he would be stepping down.
In an interview with the New Statesman, asked if he felt Mr Brown should have gone for an autumn election, Mr Straw replied: "Yes, entirely in hindsight. But I was not saying that [then]. "
He added: "There was also something practical. If the election had been called then it would have taken place after the clocks had gone back in early November."
Voters did not like elections being called "unnecessarily", he added.
"The public might have said: 'You've got a majority, why don't you use it?'
"And for a prime minister to change in mid-government is nothing unusual. Eden, Macmillan, Callaghan and Major: it has happened four times in recent decades.
"The evidence also did not appear to be that we would have won with a good majority. These were the arguments."
'Loss of nerve'
After weeks of speculation that he was about to call an early general election, Mr Brown confirmed on the BBC's Andrew Marr Show in October 2007 that he would not do so, because he wanted time to set out his "vision for change".
But Conservative leader David Cameron said Mr Brown had shown "great weakness and indecision" - while the then Lib Dem leader Sir Menzies Campbell suggested he had suffered "a loss of nerve".
In the New Statesman interview, Mr Straw also appeared to rule himself out as a future Labour leader, telling the magazine: "I am not, and would not be, a candidate for leadership in any circumstances."