New laws are coming into effect to regulate the 'dangerous overtaking of cyclists'.
Drivers who are caught breaking the rules will be given 3 penalty points and fined 120 euro under new rules.
Gardai will begin enforcing the new laws from midnight.
Road safety chiefs say drivers should give cyclists 1.5 metres of space when passing in zones with speed limits over 50kph and one metre where the limit is 50kph or lower.
The legislation has been welcomed by cycling safety campaigners.
In 2018, nine cyclists were killed on Irish roads.