He apprenticed at Wellington's Roxborough Bistro under Mark Limacher, then Michael Lambie and Andrew McConnell in Melbourne and David Thompson at Nahm in London, before taking over Attica's kitchen in 2005.
When Attica first made the list in 2010, Shewry was credited with putting the fine-dining establishment on the map.
"I know there will be much more interest in the restaurant and myself, that's inevitable. But I hope life doesn't change. I kind of like it the way it is." Shewry, who was in London for the awards, planned to celebrate the honours with friends and family.
Spain's El Celler de Can Roca in Girona took the No 1 spot from Denmark's Noma. No New Zealand restaurants made the list.
Top restaurants
1. El Celler de Can Roca - Girona, Spain
2. Noma - Copenhagen, Denmark
3. Osteria Francescana - Modena, Italy
4. Mugaritz - San Sebastian, Spain
5. Eleven Madison Park - New York, US
6. D.O.M. - Sao Paulo, Brazil
7. Dinner by Heston Blumenthal - London
8. Arzak - San Sebastian, Spain
9. Steirereck - Vienna, Austria
10. Vendome - Bergisch Gladbach, Germany
Australian restaurants in the 50 Best Restaurants 2013 list:
21. Attica - Melbourne
48. Quay - Sydney