The Commission for Racial Equality wants the Department for Education and Employment to make the data available, saying overall reductions in exclusions could be hiding hotspots, particularly for African-Caribbean boys.
Nationally, exclusions of all pupils fell for the second year running, from 12,300 in 1997-98 to 10,400 in 1998-99.
Exclusions of black children were also down, but still stood at around three times the rate for white pupils.
The Government has doubled the money available for mentors for ethnic-minority pupils, and requested action plans from education authorities which exclude a high proportion of black children.
But it has refused to identify these authorities, and has now decided not to publish the breakdown of ethnic-minority exclusions by local education authorities.
TES analysis of the previous two years' figures has shown that in some areas, black pupils were 15 times more likely to be excluded than white children.
A DFEE spokesman said of 150 English authorities, 94 only had exclusion figures for white pupils. In many cases, exclusions of other ethnic groups numbered less than four - indicatedby a hash mark (No) in the data, to avoid identifying individuals.
"A decision was taken that the tables did not allow for meaningful comparisons to be made, due to the high proportion of hash marks," he said.
"The Government is doing so much to try to eliminate the problem of ethnic minority exclusions. In the latest figures, the drop in black exclusions was slightly higher than the drop overall. However, there's still a big problem and we are not complacent."
But Phil Barnet, the commission's director of policy and communications, said: "The data has shown in previous years that there are clearly some authorities that are exclusion hotspots for African-Caribbean boys.
"If we don't have the LEA figures, that reality will be lost from sight under the national average. That's misleading and unhelpful.
"The commission does urge the DFEE to make the data available, so parents and interested organisations can see what progress has been made.
"We remain convinced of the urgent need for race-specific targets to be set for reducing exclusions, alongside the national ones."
Schools are responsible for exclusions, but the Government has set all education authorities local targets to help ensure the national exclusion rate is reduced by a third between 1999 and 2002.