The European Commissioner for Economic and Financial Affairs, Taxation and Customs Pierre Moscovici called on the EU-28 to be "ambitious" during next week's Council meeting, when decisions are to be made for the EU's tax havens black list.

Ireland, Luxembourg, Malta, and the Netherlands should be on the EU's tax haven blacklist, according to Oxfam, a global NGO.

But the four member states will be excluded because the list, to be announced next week by EU finance ministers and to be accompanied by potential sanctions, will only cover non-EU jurisdictions.

The NGO said in a report out on Tuesday that the exclusions cast doubt on the credibility of the EU list.

Speaking at the Panama Papers Committee of the European Parliament, Moscovici invited the EU governments to adopt list and sanctions: "I invite member states to urgently adopt before the end of the year the European list of jurisdictions that refuse to reform their tax rules to comply with European standards," Moscovici told MEPs during the Paradise Papers hearing.

So far, the EU member states have screened 92 jurisdictions worldwide against a set of criteria meant to measure tax transparency, use of harmful tax practices and cooperation on fiscal matters. However, even some EU member states have not changed their tax rules after EU pressure, while "half (of the remaining 92) have committed to do so in 2018" according to Moscovici.

Oxfam said in a report out on Tuesday that the exclusions cast doubt on the credibility of the EU list.

"EU governments have a choice between ending the harmful impact of tax havens on both the EU and developing countries - or whitewashing tax havens," Oxfam's Aurore Chardonnet said.

Chardonnet said the upcoming EU list was likely to be "empty" given its limited scope and given the political pressure from wealthy non-EU states such as Switzerland.

An EU so-called Code of Conduct group, set up by member states, is currently screening the jurisdictions of 92 non-EU countries to see who should be on the blacklist.

The group is using criteria based on transparency, fair taxation, and international efforts to tax profits where those profits have been made.

Oxfam applied those same criteria and came up with a list of at least 35 non-EU countries as well as the four member states.

Earlier this month, a consortium of investigative journalists published a first series of articles following a leak of some 13 million documents from the Bermuda-based law firm Appleby, which handles offshore accounts.

It showed, for instance, how Swiss commodity giant Glencore used tax tricks to shift revenues away from African national coffers.

Acknowledging the damaging extent of aggressive tax planning in the bloc, Moscovici tried to convince MEPs that an EU black list without EU member stated toed not mean that there aren't damaging tax practices in the EU. "There are damaging tax practices in EU but EU tax havens won't be on the blacklist," he said, but this does not mean that there aren't criteria. "We can't characterize member states as tax havens," added the Commissioner, refusing to comment on Oxfam's tax haven criteria. " can't comment because I am not aware of the black list", but Oxfam's interpretation is "beyond standards" according to the EU executive.

However, MEPs suggested that if EU criteria were applied to EU countries, some of them, such as Luxembourg, the Netherlands, Malta and Ireland, would end up being part of the black list, dooming the process from its outset at a Council level.

"I want to be extremely clear about the respective responsibilities: this list of tax havens will be that of the member states," added the Commissioner. According to Moscovici, "the Commission will propose to have strong and dissuasive sanctions," adding that funds provided by the EU budget, the European Bank for Reconstruction and Development and the European Investment Bank could be frozen for countries on the tax haven list.

Over the next two days at least nine MEPs from a joint delegation hailing from the EP's Panama Papers and Civil Liberties committees, will hear journalists and activists answer questions on the state of rule of law in Malta.