Labor voters in Michael Danby's Melbourne Ports have rejected his push to preference the Liberals ahead of the Greens in the marginal seat, according to a new poll.

The seat has becoming increasingly marginal due to major demographic change from its working class past to sought after inner city living.

Labor MP Michael Danby has said he wants to preference the Liberals ahead of the Greens Credit:Andrew Meares

Mr Danby's current margin is 3.6 per cent and Labor strategists have the seat, which includes St Kilda, Balaclava and South Melbourne, on a watch list of seats potentially under threat, with a major change in demographics in Albert Park and Port Melbourne favouring the Liberals.

Mr Danby has held Melbourne Ports since 1998 but requires preference flows to defeat the Liberals, who last election won the primary vote.