As captain, Williamson would face suspension if the side are fined again, with New Zealand set to play Pakistan, Australia and England in their final three group stage games.
Unbeaten New Zealand top the table on 11 points and look good for a semi-final spot but with three potentially tight matches ahead the side will be keen not to lose such an important player for the run-in.
Williamson has scored back-to-back centuries, the 28-year-old holding together New Zealand's run chase against South Africa with 106 not out and then rescuing their innings with 148 against West Indies.
He has accumulated 373 runs in four innings at an average of 186.50.
Ross Taylor is the only other player in the top-six to have provided any real contribution to New Zealand's totals in their five innings so far, with 200 runs at an average of 50.
There have been calls from former New Zealand players for coach Gary Stead to shake things up with several in the side, including openers Martin Guptill and Colin Munro, misfiring and to give others a chance to prove themselves ahead of the semi-finals.
However, Stead's predecessor Mike Hesson said there was no need to change things unless conditions warranted it and that the side now needed to aim to qualify in the top-two positions.
"It's critical for New Zealand to finish top-two with the weather in England," Hesson wrote in a column for Stuff Media.
"In a semi-final a couple of days of rain could easily happen and you don't want to be kicked out of a World Cup by the weather.
"I certainly remain confident about how far this New Zealand team can go. They haven't played the perfect game yet and they're still winning against good sides.
"That's a great sign."
(Reporting by Greg Stutchbury in Wellington; Editing by Peter Rutherford)
