Co-owner David Sullivan has claimed the majority of Birmingham supporters are 'armchair fans' who only turn out at St Andrews for high profile games.
Sullivan insisted Blues' season ticket tally of 13,700 for the 2007-2008 campaign is 'simply not enough' and that many clubs in the Championship attract bigger gates.
City attracted 24,898 fans for their opening home Premier League clash of the season against Sunderland and the figure had only slightly increased to 24,981 for the visit of West Ham at the weekend.
Sullivan said: 'This is our first year back in the Premier League and we must realise it is going to be a tough one. We are competing with many clubs who are bigger in terms of capacity and season ticket holders.
'We all know that we have one of the biggest fan bases in the country and, if these fans turn out and support us every week, we would need a 60,000 capacity stadium.
'However the reality is that most of our supporters are armchair fans unless it is a big game.
'Evidence of this was the Auto Windscreen Shield final a few years back when we took the largest following that any club had taken to the old Wembley since the Second World War (around 48,000)
'But the reality is we have 13,700 season ticket holders and that is simply not enough.'
Sullivan added: 'Many clubs in the Championship get bigger gates than us and the other promoted clubs, Sunderland and Derby, have 32,000 and 28,000 season ticket holders respectively.
'Our season ticket prices and match day admission prices are the second lowest in the division.'
Meanwhile Sullivan insisted himself and chairman David Gold would only relinquish power at Blues if someone else can improve on the work they have undertaken for the past 14 years.
Hong Kong businessman Carson Yeung has bought a 29.9% stake in the club and is understood to want to take full control within the next couple of months.
Sullivan said: 'I know some people are concerned about what is going on with the club's share-holding, I want to assure them there have been no changes.
'The club is being run by the people who have done a great job for the past 14-15 years and therefore the club is in good hands.
'We welcome the investment of Carson Yeung's company Grandtop who bought 29.9%, a minority share-holding in the club.
'David Gold and I will only cease to be majority shareholders if we think someone can do a better job of running Birmingham City than we have.'