A child psychologist is set to replace former federal workplace minister Craig Laundy as the Liberal candidate for the Sydney seat of Reid.

Fiona Martin is set to be endorsed by the party's state executive as early as Tuesday after receiving support from Prime Minister Scott Morrison.

Mr Morrison has been desperately searching for a high profile candidate to parachute into the seat, after ABC broadcaster Stan Grant and former NSW deputy commissioner Nick Kaldas knocked back his advances.

Dr Martin has beaten psychiatrist Tanveer Ahmed and the state's state election candidate for Kogarah Scott Yung to contest the federal seat next month.

The Liberal Party holds Reid by a margin of 4.7 per cent.