The Provincial Prosecutor's Office of Madrid was seeking a prison sentence for the former Real Madrid and Liverpool player, as well as a €4m fine, the Press Association Sport said in a statement.
It said Alonso is being accused of three crimes against the Public Treasury during fiscal years 2010, 2011 and 2012, when he was playing for Real Madrid.
Prosecutors accused the footballer of owing €2m in taxes from image rights earnings that he did not declare during those years.
"The representative of the Public Ministry claims the same penalty for the tax advisor Ivan Zaldua Azcuenaga and for the administrator of the company Kardazli Comercio Servicos de Consultoria e Investimentos LDA, Ignasi Maestre Casanova,” the statement read.
"Each of them, in addition, requires payment of a fine of €4m and in concept of civil liability asks them to pay jointly €2,032,845 euros to the tax agency, that is, the amount total of the economic damage caused to the Tax Administration, plus the interest generated."
Alonso has denied any wrongdoing.
He is the most recent footballer being chased by the Spanish tax authorities. Just last month, the new Manchester United player Alexis Sanchez accepted a suspended 16-month prison sentence for tax fraud in Spain after being charged with defrauding the treasury of €983,000 (£874,000) from 2012 to 2013.
Portuguese player Cristiano Ronaldo is also being investigated in a £13m tax evasion case. He has been charged with four crimes committed between 2011 and 2014, after entering a “business structure” in 2010 in a “conscious” and “voluntary” way.