Emma Raducanu and Katie Boulter will be absent when Great Britain face Australia in their Billie Jean King Cup qualifier next month.
Raducanu, the British number one and world number 24, has committed to playing the WTA 500 clay-court tournament in Linz, Austria, which runs across the same week.
Boulter, ranked 64th in the world, also misses the tie.
GB captain Anne Keothavong has instead selected Sonay Kartal, Harriet Dart, Jodie Burrage and 17-year-old Mika Stojsavljevic for the contest that will be staged in Melbourne on 10-11 April.
A fifth player can be added to the squad nearer the time.
Keothavong, who it was thought would face a tough task persuading the top British players to travel to Australia for a hard-court tie at a time when the European clay court season is getting under way, described the best-of-five encounter as “tough”.
