Water cannons from Northern Ireland have been deployed to Dublin ahead of the Queen's visit.
She is due to arrive in Ireland on May 17, the first time a British monarch has set foot in the country since it gained independence.
The British and Irish Governments welcomed it as a symbol of improving relations between the UK and Ireland but the dissident republican threat has led to some security concerns.
Drains are being checked at the quays on Dublin's River Liffey as preparations continue.
Following the murder of Catholic policeman Ronan Kerr and a Real IRA rally in Londonderry which opposed the Queen's visit, Irish Foreign Minister Eamon Gilmore said strong precautions will be put in place.
"We've seen very menacing threats coming from these groups in recent weeks," he told RTE radio.
"The Government is concerned about any dissident threats there are, and the security arrangements are very strong arrangements."
Part of these arrangements will involve two Police Service of Northern Ireland (PSNI) water cannons, which have been borrowed by Irish police.
A PSNI spokeswoman said: "The Police Service of Northern Ireland will supply equipment to An Garda Siochana for the upcoming royal visit to the Republic of Ireland from May 17-20."