The Auckland-born Leauma had been hospitalised and underwent country aft helium "suffered an mishap that caused terrible caput trauma" connected Saturday, the federation said.
Spanish media reports said Leauma fell 8 metres from a gathering successful Amsterdam.
The federation said his information had "slightly improved" connected Sunday aft country but worsened 24 hours later.
READ MORE: Iconic cricket commentator hangs up the mic
"World Rugby, and Spanish rugby successful particular, is successful mourning, and from the Spanish Rugby Federation we tin lone convey the committedness of a subordinate admired and loved by each his team-mates from XV del León [Spain's nationalist men's team] and his club, AMPO Ordizia," the federation said successful its obituary to Leauma.
Leauma, who played for the AMPO Ordizia nine successful Spain's Basque Country, was successful Amsterdam for Spain's Rugby Europe Championship lucifer against the Netherlands.
The federation said helium died due to the fact that of a "freak accident" suffered conscionable hours aft Spain bushed the Netherlands 52-7 successful a lucifer that doubled arsenic a qualifier for the adjacent Rugby World Cup successful France successful 2023.
Watch the 2022 Japan Rugby League One play from January 8 connected Stan Sport, advertisement free, unrecorded and connected demand. Start your 7 time escaped proceedings here!
He was poised to marque his authoritative planetary debut for Spain aft becoming eligible done 3 years of residency, but helium was withdrawn astatine the past infinitesimal due to the fact that of doubts astir his eligibility. He played successful a affable for Spain against an Italian broadside successful Madrid successful October.
The federation said its president Alfonso Feijoo and Ordizia sports manager Iñigo Marotias would conscionable Leauma's woman erstwhile she arrived successful Amsterdam.
In its obituary, Leauma was described arsenic "a idiosyncratic who made himself loved" and made his people connected Spanish rugby.
At 197cm and weighing 110kg, Leauma was hoping to go a regular successful Spain's team.
The federation said they would honour his representation by trying to suffice for the World Cup for the archetypal clip since their lone quality successful the UK successful 1999.
Leauma played for a fistful of Auckland clubs, including Otahuhu, Papatoetoe, Mount Wellington and Manukau Rovers.
A blindside flanker, No 8 oregon lock, helium represented Samoa's under-20s and played for Auckland's sevens team.
Leauma besides took his rugby vocation to Australia, playing for the Sydney Rays and West Harbour clubs successful New South Wales, earlier moving to Spain successful 2018.
The Mount Wellington and Papatoetoe clubs led the tributes for Leauma connected societal media.
"These posts aren't casual to bash and this 1 successful peculiar is beauteous upsetting arsenic this nine acknowledges the passing of Kawa Leauma," Mount Wellington's Facebook station said.
"Kawa was an integral portion of our Mount Wellington Premier side, large subordinate and humble some connected and disconnected the tract and we enjoyed seeing him proceed to thrive beyond his clip astatine our club. He volition beryllium sorely missed by galore of our assemblage and we widen our sincere condolences to his woman and household arsenic they navigate this pugnacious clip successful a overseas country."
Papatoetoe tribute's said "another member gone mode excessively soon".
"Our sincere condolences spell retired to the household and friends of Kawwa Leuma who passed distant successful a tragic mishap whilst surviving overseas successful Spain," the club's Facebook station said.
"Kawwa had been playing nonrecreational rugby and conscionable precocious made his planetary debut for Spain. He was portion of a beardown Papatoetoe U21s squad backmost successful 2010.
"Rest successful emotion member Kawwa."
World Rugby president Sir Bill Beaumont tweeted: "Deeply saddened to perceive of the passing of Spain planetary Kawa Leauma. My thoughts are with his teammates & household astatine this hard time," Beaumont tweeted.
For a regular dose of the champion of the breaking quality and exclusive contented from Wide World of Sports, subscribe to our newsletter by clicking here!