
The party had earlier staked its claim on Tuaran which was won by Upko president Wilfred Madius Tangau in 2018.
DAP and Upko are both members of the opposition Pakatan Harapan coalition.
PBS president Maximus Ongkili said the party is gunning for Tenom on behalf of the ruling Gabungan Rakyat Sabah, which also includes Sabah Bersatu, Parti Solidariti Tanah Airku (STAR) and Sabah Progressive Party (SAPP).
Ongkili is MP for Kota Marudu, the sole seat won by PBS in May 2018.
Loud applause greeted his announcement at the opening of the Melalap and Kemabong divisional annual meetings today.
Noorita Sual of DAP won Tenom in a three-way fight in 2018.