The Competition Authority is to carry out an in-depth study of ports in Ireland.
The Government plans to use private equity investors to fund the expansion of Irish ports but it has ruled out selling off strategically important facilities.
Transport Minister Leo Varadkar said a study by the Competition Authority into Ireland's ports would examine whether Dublin Port had an economically dominant position.
Minister Varadkar said: "Dublin Port is hugely successful with 40% of our GDP going through it."
He added that "part of our study will look at whether it is profitable because it is dominant or because it is very competitive."
The minister said "it is operating a competitive model with different terminals competing with each other. We want to make sure our traders and exporters are getting the best value out of State companies."
Mr Varadkar said that the Government wanted 30% of profits from ports paid to the State in dividends.
He also said the Government is very much open to private equity investment in ports but it did not have plans to sell any of the ports that are strategically important.
He said private money could be invested ports. At present the facilities do not get State aid or capital funding.
Dublin Port Company has said it looks forward to engaging with the Competition Authority as it carries out its work.