"We always assess the most competitive sources of oil, in which Iran is included when it becomes a competitive and trustworthy partner," Galp's chief executive, Carlos Gomes da Silva, said at a news conference in London.

In comments to journalists, da Silva noted that "Iran was a partner for Galp, as are various others in the Middle East" - a relationship that was interrupted by the imposition of the embargo on oil imports from the country.

"We use a model of economic optimisation and so we look at all crudes that are available and [see] which are of most interest," he added.

Da Silva noted that, despite the formal lifting of sanctions, the embargo has not yet been fully removed.

On 16 January the US, European Union and United Nations Security Council lifted all the sanctions that were imposed on Iran because of its nuclear programme.