Kells is expanding with the acquisition of Martin & Holmes Legal from April 1.
The move sees the number of offices in the Illawarra and Sydney grow to six.
Martin & Holmes Legal has operated from Kiama area for more than 20 years.
Its directors Peter Martin and Peter Holmes said the acquisition by Kells was a natural fit as the two firms have shared values and many synergies.
From April 1 Martin & Holmes Legal will take on the Kells name.
Mr Martin and Mr Holmes will remain at the practice.
Mr Holmes said the merger will strengthen the Kiama office's law offering for many years to come.
They are great people who have built a very impressive businessPaul Magagnino
Kells managing partner Paul Magagnino said it was great to have the highly regarded team at Martin & Holmes' join the firm.
"They are great people who have built a very impressive business and are just as driven as we are in providing exceptional legal services and value to clients," eh said
"This acquisition strengthens our position. And boosts our capabilities to the Kiama and south coast communities.
"With our shared philosophies and values, coupled with our combined experience, this acquisition is a perfect match and a natural progression for the future growth of Kells which presently has 65 staff in Sydney and the Illawarra".