Four uncapped players were named, with Glasgow forwards Rob Harley and Ryan Grant joined by Edinburgh flanker David Denton and Bath full-back Jack Cuthbert with 10 players to be dropped from the selection by the August 22 deadline.
Robinson said: "There's competition for places right across the board and that's what we wanted.
"We wanted a trimmed down squad and players challenging to get into the 30.
"It just shows the improvements that we've made over the last three or four years that there is that competition there."
Perhaps the position that best illustrates the competition is scrum-half where Rory Lawson, Mike Blair, Chris Cusiter - all of whom have captained Scotland under Robinson - and Greig Laidlaw are battling for a place on the plane to New Zealand.
Cusiter has not played a Test for Scotland since the 2010 RBS 6 Nations due to a knee problem and featured in just three matches for Glasgow at the end of this season.
The 28-year-old has arrived in Australia and will play up to four matches with Sydney-based Southern Districts before returning for Scotland's summer training camp, which begins on June 20.
Cusiter will then hope to play in the warm-up Tests with Ireland (August 6) and Italy (August 20) at Murrayfield and force his way into the final travelling party for New Zealand.
Laidlaw has played fly-half for Edinburgh of late and is a strong goal-kicker, his versatility enhancing his prospects of travelling.
Robinson already has in his mind a number of players near-certain to make the final squad, fitness permitting, with Scotland's World Cup campaign beginning against Romania in Invercargill on September 10.
He added: "We've been working together with a consistency of selection over the last two years so obviously there will be players that I already have pencilled in, but they've still got to work hard and reach targets that we're setting."
Those players already earmarked for places are likely to include captain Alastair Kellock, Richie Gray, John Barclay, Ross Ford and Allan Jacobsen, all of whom were made unavailable for the final weeks of the Magners League season with the World Cup in mind.
Should Chris Paterson, Scotland's most-capped player and highest points scorer, be included in the final squad he would become the first Scot to play in four World Cup tournaments.
Robinson said: "It just shows his durability, his competitive spirit and how he has really looked after himself throughout his whole career.
"He's a player I really enjoy working with."
Paterson is one of the reasons Cuthbert remains uncapped.
Robinson added: "Jack Cuthbert has been in the squad and was unlucky not to have an opportunity to be in the 22 during the Six Nations and really that was down to the form that Chris Paterson showed."
Harley is another player who was on the verge of Six Nations selection, only to narrowly miss out, while Robinson has been impressed with Glasgow prop Grant and Denton, the Edinburgh back row.
Robinson will hone his squad's fitness and skills over the summer months in preparation for the World Cup.
He added: "Focusing on the basics is key for us in having success in New Zealand."
After the clash with Romania, Robinson's men play Georgia in Invercargill on September 14, Argentina in Wellington on September 25 and England in Auckland on October 1, with two teams from the pool progressing to the quarter-finals.
Robinson, who was forwards coach when England won the 2003 World Cup in Australia, has previously said he believes Scotland could top the group, but also that Romania and Georgia could be potential banana skins.
To avoid being on the wrong end of an upset Robinson says it is important Scotland do not to get too far ahead of themselves.
He added: "It's focusing on each game and taking a step-by-step approach.
"We've got to get into our preparation and the selected 15 to play against Romania has got to play very well.
"We've got a four-day turnaround to playing Georgia, so we'll have to get our recovery right and take on what is quite a physical side and a team that will be selected full of French-based players.
"And then we've got a 10-day turnaround before we play the two top-seeded teams, Argentina and England.
"That's why the focus has to be on those first two games, making sure we're absolutely spot on to get everything we can out of them."
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