The missiles, which were thrown by anti-war protesters, did not hit the former prime minister as he arrived at a bookshop in Dublin.
Activists clashed with Gardai as they tried to push down a security barrier outside the Eason store on O'Connell Street.
Campaigners, who turned out in the pouring rain, were chanting: "Hey hey Tony hey, how many kids have you killed today?" They also shouted: "Tony Blair war criminal" and "blood on your hands".
Undercover detectives mingled with the crowds taking names before Mr Blair arrived at the shop at about 10.30am on Saturday.
The city tram service was suspended as Gardai blocked off streets surrounding the city centre store. Shops in the area also closed, with Penny's department store pulling down its shutters as scuffles broke out.
It is the first book signing since Mr Blair's memoirs were released this week. The book, A Journey, tells of his life in politics and has become one of the fastest selling autobiographies on record.
Mr Blair, who gave his first live television interview to Irish state broadcaster RTE on Friday night, was expected to spend about an hour at the store.
Mr Blair said the Northern Ireland peace process was one of the few moments in politics that he felt really proud.
Now the Middle East peace envoy, he described watching former Northern Ireland First Minister Ian Paisley and Deputy First Minister Martin McGuinness sitting together publicly for the first time. "It was just such a strange and extraordinary sight and one of the few times in politics I felt really proud actually," Mr Blair said.