Australia's under-19 bowlers have made an impressive start in the men's U19 World Cup, dismissing Namibia for less than 100 to set up a resounding victory in Kimberley, South Africa.

Chasing 92 to win the batters lost six wickets as they focused on winning quickly, wrapping up a four-wicket win with more than 30 overs to spare.

Queensland pace bowler Callum Vidler was man of the match, taking 4-17 as Namibia were dismissed for 91 off 33.1 overs.

Vidler took a brace of early wickets as Namibia were reduced to 2-6 in the sixth over on Monday, then returned to pick up a couple more.

He was well supported by NSW pacer Tom Straker, who took 3-16 while another quick, West Australian Mahli Beardman, snared 2-15.

Skipper Hugh Weibgen, from Queensland, made 39 off 43 balls to anchor Australia's reply, hitting a pair of fours in the 20th over, one to level to scores, one to seal victory.

However, only Harry Dixon and Raf MacMillan also reached double-figures, each making 16.

Australia's next match is on Thursday (1900 AEDT) against Zimbabwe, who lost their opening match on Sunday to Sri Lanka, the other team in the group.

The top three teams from each of the four groups will qualify for the Super Sixes stage, divided into two groups of six, before a last-four knock-out.

Australia are bidding for a fourth success. They last won the competition in 2010 when Kane Richardson and Josh Hazlewood shone in the final, in a team that also included Mitch Marsh.