"Ekulama I is up," the spokesman said on Friday, referring to the last of several flow-stations to reopen after angry villagers from the Kula community forced Shell to shut down the facilities on 5 December.
The shut-down caused a production loss of about 130,000 barrels per day of crude oil exports from the Bonny export terminal.
Shell is Nigeria's biggest operator, accounting for almost half of the west African country's daily exports of 2.5 million barrels.
The Anglo-Dutch oil giant has in the past week gradually reopened three other plants - Belema, Santa Barbara and Ekulama II - which led to a resumption of 65,000 barrels per day out of the 130,000 total.
A spokesman could not say if the reopening of the Ekulama I plant on Friday would enable Shell to reach the peak production of 130,000 barrels per day from the protest-hit stations.
"I will advise on production rates later in the afternoon," he said.
Community unrest had forced Shell to shut down the stations accounting in December last year when villagers from Kula briefly occupied them.
The shut-down forced Shell to warn clients it would not be able to meet export contracts from its Bonny terminal until early next month.
Nigerians earn little from oil
compared with multinationals
The company reopened Ekulama II on Wednesday after successfully carrying out inspection checks on the facility.
Last week, the company resumed production of 47,000 barrels with the reopening of its Belema and Santa Barbara plants in Rivers State.
The spokesman said on Friday the company was negotiating with protesters who last week attempted to occupy the Odeama Creek station, about 30km to the west of Ekulama, causing a production loss of 8000 barrels.
The villagers were protesting because a power generator provided for them by Shell had broken down and they expected the company to repair it.
"We are still repairing the generator. Hopefully by next week the job would have been done and we will restart the plant," the spokesman said.
Shell, like most oil majors operating in the coastal swamps of the oil-rich but troubled Niger delta, is regularly the target of community protests and hostage-taking.