The couple were booed on the street outside Barcelona's famous Gran Teatre del Liceu and then again when they entered, reported El Mundo newspaper on Friday.
Footage of the reception showed Crown Prince Felipe and his wife Letizia looking nonplussed after their mixed greeting in the the theatre.
There were however, plenty of cheers as the Princes of Asturias and Girona took their seats for a performance of The Elixir of Love, an opera by the Italian composer Gaetano Donizetti.
The couple were able to raise smiles as the positive welcome drowned out the dissenting jeers.
The audience reaction showed a "lack of respect", the Secretary General of Spain's ruling Popular Party told radio station Cadena Cope.
"Anyone attending a cultural event has a right to be respected," said Cospedal during the interview.
Spain's Royal Family has seen its popularity fall in recent times, largely because of a high profile corruption case involving the King Juan Carlos' son-in-law, Iñaki Urdangarin.
Urdangarin — married to the King's second oldest daughter, the Infanta Cristina — is currently being investigated for his possible involvement in the diversion of funds from the charitable sports foundation, the Nóos institute.
Cristina is also in the firing line. A judge in Palma de Mallorca also demanded on May 24th that the tax authorities provide him with a report on Cristina's property and non-property assets, investment funds, financial assets and deposits, a copy of the order showed.
A poll run by Spain's left-wing El País newspaper in April showed that 53 percent of people surveyed disapproved of the way the 75-year-old King Juan Carlos was carrying out his functions, against 42 percent who approved.
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That gave him an overall approval-versus-disapproval rating of -11, compared to +21 in December, a lower rating than the one received by tax inspectors or lawyers and the first time that he has received a negative rating.
Felipe's approval ratings have also taken a hit but remain broadly favourable.
A majority of Spaniards, 61 percent, approve of Felipe against 33 percent who disapprove, giving him an overall approval-versus-disapproval rating of +28, compared to +37 in December.