Iran's new oil industry investment contract for international oil firms will be ready by July, a senior Oil Ministry official was quoted as saying on Thursday by Iranian state TV.

"The new contracts will be ready in June, July ... Hopefully we will have oil tenders in July ...We welcome investors from all countries," Deputy Oil Minister Rokneddin Javadi said.

Some 135 companies including BP, Total, Italy's Eni and Spain's Repsol attended a conference in Tehran in November to hear about the new Iran Petroleum Contract (IPC) but its launch has been postponed several times.

Hardline rivals of pragmatist President Hassan Rouhani have criticised the IPC, which would end a buy-back system dating back more than 20 years under which foreign firms have been banned from booking reserves or taking equity stakes in Iranian companies.

Yet Iran aims to sweeten the terms it offers on oil development contracts to attract foreign investors deterred by years of sanctions.

Those sanctions were lifted in January under a deal reached between Iran and six major powers which calls for Tehran to curb its nuclear programme. Opec member Iran now aims to return its oil production to pre-sanctions levels.

"Iran's oil exports are expected to increase in the coming days to 2.2 million barrels per day (bpd)," Javadi said.

Iran's output has risen to 3.7 million bpd, the Oil Ministry's official website Shana reported.

"Iran's oil exports reached 2.1 million bpd in the month of Ordibehesht (which started on April 19). Our oil exports were around 2.2 million bpd before sanctions," state news agency Irna reported Javadi as saying.

Iranian officials have said they expect Tehran to attain its pre-sanctions output level by the end of the Iranian month of Khordad, which falls on June 20.

Facing oversupply that is weighing on crude prices, Opec and non-Opec producers sought to agree to freeze their output levels last month but failed after Saudi Arabia insisted that all Opec members, including Iran, agree to do so.

"Iran can get involved in any oil policy-making discussions after regaining its pre-sanctions oil output (level)," Javadi said on the sideline of Iran's 21th international Oil and Gas conference in Tehran.

Javadi's comments suggests that Iran might be willing to join a renewed effort to restrain output when Opec members meet in Vienna on June 2.  - Reuters