One of the Lindt cafe staffers who survived the December siege says it's extremely important for him to be at the store's reopening today.

Joel Herat was back behind the counter when the doors reopened at 10am at the Martin Place store in Sydney, three months after gunman Man Haron Monis held 18 staff and customers captive.

He received a hug from NSW Premier Mike Baird, who chatted with staff in the cafe before the reopening.

Two plaques were to be unveiled at the store today to commemorate the lives of cafe manager Tori Johnson and barrister Katrina Dawson, who along with Monis died when the siege ended in a hail of gunfire.