MADRID, Dec ‌12 (Reuters) - Spain's Socialist Party PSOE apologised on Friday for "communication failures" in ‍handling ‌sexual harassment complaints, as mounting allegations threaten the credibility of a party ⁠that has long championed women's rights.

The ‌party, led by Prime Minister Pedro Sanchez, is under fire from unions, the opposition and its own coalition partners over accusations that it created an internal platform for ⁠women to report harassment or abuse after a case emerged in July — but then failed to ​act on complaints submitted through it.

PSOE secretary Rebeca ‌Torro told reporters on Friday that ⁠stronger support mechanisms would be implemented, but denied the party sought to suppress accusations. "If we say we are feminists, we mean it. PSOE ​defends women's rights," she said.

Sanchez, who is already warding off reputational damage from corruption scandals involving his wife, brother and senior party figures, has loudly championed his feminist credentials, appointing more women than men to top government ​posts ‍for the first time ​in Spain's history when taking office in 2018.

But women in his party, as well as Yolanda Diaz, the leader of PSOE's leftist junior coalition partner Sumar, have decried an apparent failure to deal with allegations of sexist or abusive behaviour.

These include harassment allegations surfacing in local media against several junior party ⁠officials.

"This type of behaviour tears us up from the inside," said Angeles Ferriz, the party's deputy spokesperson in ​the region of Andalucia. "We cannot allow the PSOE's feminist DNA to be called into question."    Unai Sordo, the leader of one of Spain's largest unions, the CCOO, demanded zero tolerance for harassment, alleging ‌it stemmed from entrenched machismo in Spanish society. 

(Reporting by Victoria Waldersee and Emma Pinedo. Additional reporting David Latona, editing by Aislinn Laing and Ros Russell)