Kerry County Council has issued warning notices to 26 staff as investigations continue into planning applications for 2000.
A senior engineer has been suspended for seven days and reassigned to other duties, and another officer has received a warning and had his probationary period extended.
According to a statement from the council, the suspension followed a complaint relating to development work on lands owned by the officer for which planning permission had not been obtained.
The internal investigation related to complaints by members of the public against two members of staff, and an examination of all planning applications in each of the four local authorities during 2000.
County manager Mr Martin Nolan said there is no evidence of any improper influence being brought to bear on planners, but he said there was "a deficiency in the standard of conduct of a minority of staff".
The Minister for the Environment has written to each County manager asking for an examination of the situation under their control according to Mr Nolan.
"These investigations have been conducted as a result of complaints submitted to me by members of the public and as a result of concerns about the involvement of staff of the Local Authorities in Kerry in the preparation of planning applications," he said.
Mr Nolan said a new Code of Conduct will come into effect from May, and requires an officer who proposes to engage in any outside occupation to inform the County Manager first.