BBC
English-language Press TV had said the Netherlands, Greece, France, Portugal, Spain and Italy would be affected.
But an oil ministry spokesman told the Reuters news agency that any such decision would be announced by Iran’s Supreme National Security Council.
EU member states have agreed to stop importing Iranian crude from 1 July.
The move is intended to pressure Tehran to stop enriching uranium, which can be used for civilian nuclear purposes but also to build warheads.
Iran insists its nuclear programme is peaceful, but the UN’s International Atomic Energy Agency says it has information suggesting Iran has carried out tests “relevant to the development of a nuclear explosive device”.
The EU oil embargo, which was agreed last month, was phased so member states that were relatively dependent on Iranian crude – notably Greece, Spain and Italy – had enough time to find alternative sources.
Graphic image showing Iran’s top oil export destinations
The bloc currently buys about 20% of Iran’s oil exports, which account for a majority of government revenue. However, Iran’s Oil Minister Rostam Qasemi said that a cut in exports to Europe would not hurt Tehran.
Brent crude oil prices were up $1 a barrel after Press TV’s announcement on Wednesday, but the European Commission said such a move would make little difference as member states were already switching suppliers.
“Oil is something you can get on the international markets, and Saudi Arabia said they would increase their production,” a spokeswoman for EU Energy Commissioner Guenther Oettinger, told the AFP news agency.
The reports about the halt of Iranian oil exports to the six EU states came shortly before President Mahmoud Ahmadinejad was expected to unveil a new generation of domestically made uranium enrichment centrifuges.
State TV also said Mr Ahmadinejad would announce Iran had produced its own 20% uranium-enriched fuel rods for a research reactor in Tehran.
