The midfielder has been an integral part of the Birmingham side since McLeish's arrival three years ago but is out of contract at the end of this season.
Talks over a fresh agreement have been continuing for several months and, with the former Arsenal trainee free to speak with other clubs from January, McLeish is determined to bring the matter to a conclusion.
Negotiations: Larsson (left) has been in talks about a new Birmingham deal
He said: 'We haven't spoken to his agent for a month or so and I'm aware that we need to get things done before the New Year.
'Seb has played at a high level this season and he has kicked on. I'll be sitting down with chief executive Peter Pannu and I'm sure I'll get the chance to sort this out. It's something I'll be looking to get done, certainly.'
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