Lafferty, 28, has been unable to command a first team place with Norwich City and wants to be playing regularly before the Euro 2016 tournament.
Steve Evans said Lafferty was among the players he wanted in his attempt to strengthen the squad at Elland Road.
"The clubs are having a chat. We will see where it goes," Evans said.
Lafferty has made only two appearances in a Norwich shirt this season.
The former Rangers star scored as the Canaries beat West Bromwich Albion 3-0 in the Capital One Cup and was a late substitute in a Premier League home defeat by Leicester City.
Lafferty's form will be crucial to Northern Ireland as they make their first ever appearance in the European Championship finals.
The County Fermanagh man, who started his English League career as a teenager with Burnley, scored seven goals in his nine appearances during the successful qualifying campaign.
His late equaliser in the home fixture with Hungary in September proved pivotal for Michael O'Neill's men who went on to top Group F.
O'Neill is worried about the fact that his top striker has been playing reserve team football for most of the season, and a move to Championship side Leeds would allay that concern.