A Matt Duffie double helped Melbourne Storm boost their hopes of a top-four finish with a convincing 30-2 victory at Cronulla Sharks on Monday.

Melbourne have been something of a bogey team for Cronulla in recent years, the Storm winning nine of the past 10 NRL encounters between the teams.

And the Sharks were second-best once again on this occasion, Duffie scoring in each half to add to Jesse Bromwich's opening try, before Dale Finucane and Cameron Munster crossed late on in a fast-paced and physical encounter.

The Storm, who had won their previous five matches, were the more clinical in an even first half and scored the first try of the game in the 12th minute when Cooper Cronk offloaded to Bromwich, who tore through a gap in the hosts' defence.

Cronulla were up against it six minutes later when their opponents worked the ball from left to right, Munster's excellent long pass allowing Duffie to touch down in the corner.

Sosaia Feki did ground the ball for Cronulla before half-time, but the try was disallowed after it was ruled unfair contact had been made with Duffie in the air earlier in the play.

Melbourne's defence had to withstand a sustained spell of pressure from the Sharks during the second half, and their resilience reaped rewards when Duffie scored his second try with just over 10 minutes remaining.

Finucane then pounced on a loose ball to score after Cronk collided with a post in an attempt to grab the ball in the air, before Munster scored a counter-attacking try from his own half in the last minute.