In various sandstone cloisters around the nation, highly-paid vice-chancellors are wondering where their next bonus might come from.

A key cog in their money-making machines has just been removed with transitions from international student visas to 457 visas halving last year.

Parliamentary Library researcher Henry Sherrell, who keeps a close watch on matters of visas and immigration, has spotted the quiet release of 457 visa statistics for the December half.

The trend he identified in the September quarter has continued - 457 visa applications for the six month period were down by 34 per cent on the previous corresponding period.