During the visit this week, MEPs questioned several people as part of their inquiries into the Panama Papers scandal.
These included Edward Scicluna, the Maltese minister for finance, Labour party minister Konrad Mizzi and Beppe Fenech Adami, Nationalist party shadow minister for home affairs.
After returning to Brussels, delegation member Miguel Viegas, said, "It is disappointing that some of the central figures named in the Panama Papers and other tax evasion and money laundering scandals refused to meet with the parliamentary inquiry committee - namely, the Maltese Prime Minister's chief of staff, Keith Schembri and the Nexia BT accountants who set up the structures named in the Panama Papers."
Others who refused to meet the delegation include the former resources and infrastructure minister Ninu Zammit, who had incorporated a company in the British Virgin Islands through Mossack Fonseca, the company at the centre of the scandal.
Viegas said that two things were clear for the delegation after the visit to Valetta.
"First," he said, "members of both the Conservatives and the Social Democrats in Malta have serious questions to answer relating to their involvement in money-laundering and tax evasion as exposed in the Panama Papers.
"Second, despite some divisions, both sides of the political spectrum closed ranks to defend the Maltese tax system, which provides significant advantages for multinationals engaging in tax avoidance, particularly for those relating to intellectual property.
"In this regard, Malta is not different from other EU countries such as Luxembourg or the Netherlands."
The delegation met the Financial Analysis Intelligence Unit (FIAU); the Maltese financial services authority and investigative journalists.
The Portuguese MEP added, "The partisan polarisation of the debate arising from the Panama Papers in Malta is extreme and was evident among members of the Maltese government and opposition, the Maltese MEPs participating in the fact-finding mission, and the various media outlets reporting on the Panama Papers in Malta."
During the meetings, Viegas questioned Scicluna on Malta's opposition in the European Council to several anti-tax avoidance initiatives including the common consolidated corporate tax base (CCCTB) and whether Malta could be relied upon during its Presidency of the Council to ensure progress is made on these initiatives.
Viegas said, "While Malta is clearly benefitting from the presence of multinationals, this comes at a cost to other countries estimated at €14bn between 2012 and 2015 as a result of Malta's 'full imputation' tax system.
"I welcome Scicluna's commitment to the our fact-finding mission that, despite his personal opposition to initiatives such as the CCCTB, Malta intends to play a proactive role in the Council to ensure the approval of anti-tax avoidance measures including the CCCTB."
Among others who met the MEPs were Matthew Vella, editor of Malta Today newspaper which has closely followed the Panama Papers story.
Vella said, "The MEPs were mainly interested in Malta's financial services system and tax regime, the role of gaming companies, and the oversight of the police on money laundering. They were keen to know why both main political parties are so disinterested in reforming the taxation system."
He added that no MEP said outright that Malta is a tax haven, but they did have an impression of Malta as a country that is good for business where tax is concerned.
He said, "Many companies make money in a foreign country, transfer the money to a Maltese bank account, pay taxes in Malta, and then request a discount on those taxes.”"
Vella said that many MEPs, including German ones, are interested in this system "because they think that German companies come to Malta to avoid paying tax in Germany."
He said, "I told them that there are some Maltese politicians who have financial interests in companies, that a degree of intimacy exists between the financial services class and the political class - which is why there is no political will or enthusiasm towards tax reform and tax justice.
"The Panama Papers exposed a global kleptocracy and, although Malta is not Panama, it does play a small part in the whole system."