Irish drivers could be hit with three penalty points and a fixed charge fine of up to €120 for overtaking cyclists in a dangerous fashion.
The new regulations aimed at ensuring the safety of cyclists will come into affect from midnight tonight.
Minister for Transport Shane Ross increased the fine from €80 to €120.
The move comes after 40 cyclists were killed on Irish roads since 2016.
While the fine was increased, the number of penalty points a motorist can receive remains the same, as changing this would require passing fresh legislation.
A number of cycle groups have called for minimum passing distances to become a legal requirement but the Attorney General has warned that it would be difficult to enforce.
Cycling experts recommend that drivers give cyclists 1.5 metres of space when overtaking in areas with speed limits of more than 50km/ph and 1 metre when the speed limit is 50km/ph or lower.
Speaking on RTE's Morning Ireland, Clara Clark of the Dublin Cycling Campaign said the changes were a step in the right direction but urged drivers.
She said: "Cyclists are vulnerable, a cyclist is a very tiny person on a very tiny piece of machinery, and a car is a big soundproof box of steel, so they have got to make provision for the space on the road and just become aware... I am pleading today with motorists to do the enforcing themselves to just slow down and create a bit of space."
