The Aberdeen company, which is focused on exploration and production in West Africa, had previously indicated it would be able to re-open the onshore Opuama Production Facility this month and begin producing oil from the OML 40 licence it has a stake in.
In an operational update Eland said it has been working closely with state-owned operator the Nigerian Petroleum Development Company (NPDC) "in a challenging operating environment" to repair infrastructure which has deteriorated since the site was closed in March 2006.
While fabrication and installation of flowlines for wells are completed, issues must still be tackled before production can start.
There are 14 miles of a 22 mile export pipeline which have still to be repaired with Eland anticipating it will be completed in the next three to four weeks.
Purchasing of major components for the flowstation on the site has started with work on that area expected to last up to five weeks. Eland said it is confident production will start before the end of 2013.
The company added: "While this is a deferment from the previously [suggested] October, comfort can be drawn from the fact that work on all components is underway and is being vigorously monitored for ways of improvement."
The production rate from restarting two existing wells is expected to be more than 2500 barrels of oil per day by the end of the year.
Drilling of six development wells on the Opuama Field, which is thought to contain more than 54 million barrels of oil, is pencilled in for next year.
Eland said it is waiting on a rig - currently being used by Conoil in a separate Nigerian field - which should be released in early 2014. The target is for each subsequent new well to increase production by around 3000 barrels of oil per day.
Les Blair, chief executive of Eland Oil & Gas, said: "Our immediate focus is to restore oil production on OML 40 and we have a close working relationship with the Operator, NPDC, to achieve this goal.
"In parallel we continue planning for the extensive development drilling campaign on OML 40, starting with six wells on the Opuama Field.
"The delays we have experienced are frustrating but not unexpected in a project of this complexity and in the environment in which we are operating."
Analysts said the long-term prospects for Eland still look strong.
Northland suggested production and cashflows are both likely to ramp up through 2014 and added: "We expect that significant momentum can be achieved next year, given the six well programme in place."
Brokers at Davy said: "While the production start-up is clearly late and the drilling schedule has also shifted, the underlying long-term investment theme in Eland has not changed. The group provides access to, and development of, material quantities of oil in a proven production region."
Mr Blair said the Eland management team has a lot of experience of working in Nigeria and established strong relationships with stakeholders.
He added: "This will stand the Company in good stead to unlock the value inherent in OML 40, which will be amply demonstrated when the drilling campaign gets underway."
Shares closed down 5.5p at 102.5p.