Taxi-drivers, who had up until now enjoyed an exemption on safety grounds, will be obliged by law to wear seatbelts from next Thursday.
The Minister for Transport, Mr Brennan, said in a statement that he was ending the exemption for taxi, hackney and limousine drivers from Thursday, July 1st.
He said the proven effectiveness of seatbelts in preventing death and serious injury outweighed the benefits to these drivers of not wearing them.
"The safety of 14,000 drivers and their passengers has to be paramount," Mr Brennan said this afternoon.
Taxi-drivers argue that they could be vulnerable to attack from passengers if they were forced to wear seatbelts.
The president of the Irish Taxi-Drivers' Federation, Mr John Usher, said his union's 3,000 members were against the move, as they were concerned seatbelts could be used to choke them.
However, Mr Brennan said there was no evidence to suggest this was a real risk to drivers, as there have been "very few" such incidents.