That left Leinster firmly in control by half-time as they led 18-6. Munster's points came courtesy of two Gary Jones penalties.
On the resumption, it proved to be more of the same from the eastern side and backed by nature's elements, the scores began to come for the men in blue at a frenetic pace.
Ian Leonard, Donagh O'Shea and a hat-trick from St. Mary's College clubman Darragh Fanning had Leinster cruising by the 55th minute mark.
And although Kevin Lynch sneaked in behind the Leinster cover for Munster's only try, Collins and Leonard wrapped up a resounding home win in the concluding stages.
The Series final will take at Monkstown's grounds at Sydney Parade on Wednesday, December 17, with Ulster standing in Leinster's way.
Seeking their first Interpro title, Ulster progressed to the final with a fine 58-8 win over Connacht in Enniskillen on Tuesday.
LEINSTER COLLEGES: M Geraghty; C Marron, L Kavanagh, G Coffey, D Fanning; B Collins, D Toman; J Roe, C Culleton, I Leonard, R Copeland, R Smith, J Downey, E Nihill, A Dunlop.
Replacements: D O'Shea, C Hogan, R O'Neill, N Lawless, D Hegarty, B McCarthy.
MUNSTER COLLEGES: I Watchorn; J English, G Jones, K Lynch, C Burkley; E Tubridy, C Nagle; F Lawlor, B Duggan, TJ Relaghan, D Barry, J Gilmartin, S Hassett, S Young, S Melbourne.
Replacements: K Maggs, K Murphy, J McSweeney, E White, D Sheridan, E Cullinane, N McGrath, D Murphy, S Casey.
Referee: David Keane (IRFU)