diff --git a/icu4c/source/tools/pkgdata/pkgdata.cpp b/icu4c/source/tools/pkgdata/pkgdata.cpp
index 1b6d2012afb1..ea98b3fc962c 100644
--- a/icu4c/source/tools/pkgdata/pkgdata.cpp
+++ b/icu4c/source/tools/pkgdata/pkgdata.cpp
@@ -1140,7 +1140,7 @@ static int32_t pkg_createSymLinks(const char *targetDir, UBool specialHandling)
 
 static int32_t pkg_installLibrary(const char *installDir, const char *targetDir, UBool noVersion) {
     int32_t result = 0;
-    char cmd[SMALL_BUFFER_MAX_SIZE * 2];
+    char cmd[LARGE_BUFFER_MAX_SIZE];
 
     auto ret = snprintf(cmd,
             sizeof(cmd),
@@ -1211,7 +1211,7 @@ static int32_t pkg_installLibrary(const char *installDir, const char *targetDir,
 
 static int32_t pkg_installCommonMode(const char *installDir, const char *fileName) {
     int32_t result = 0;
-    char cmd[SMALL_BUFFER_MAX_SIZE] = "";
+    char cmd[LARGE_BUFFER_MAX_SIZE] = "";
 
     if (!T_FileStream_file_exists(installDir)) {
         UErrorCode status = U_ZERO_ERROR;
@@ -1243,7 +1243,7 @@ static int32_t pkg_installCommonMode(const char *installDir, const char *fileNam
 #endif
 static int32_t pkg_installFileMode(const char *installDir, const char *srcDir, const char *fileListName) {
     int32_t result = 0;
-    char cmd[SMALL_BUFFER_MAX_SIZE] = "";
+    char cmd[LARGE_BUFFER_MAX_SIZE] = "";
 
     if (!T_FileStream_file_exists(installDir)) {
         UErrorCode status = U_ZERO_ERROR;
diff --git a/icu4c/source/tools/toolutil/pkg_genc.h b/icu4c/source/tools/toolutil/pkg_genc.h
index 2dd1b45cde99..f811fe532349 100644
--- a/icu4c/source/tools/toolutil/pkg_genc.h
+++ b/icu4c/source/tools/toolutil/pkg_genc.h
@@ -59,9 +59,8 @@
 #define PKGDATA_FILE_SEP_STRING U_FILE_SEP_STRING
 #endif
 
-#define LARGE_BUFFER_MAX_SIZE 2048
-#define SMALL_BUFFER_MAX_SIZE 512
-#define SMALL_BUFFER_FLAG_NAMES 32
+#define LARGE_BUFFER_MAX_SIZE 16384
+#define SMALL_BUFFER_MAX_SIZE 4096
 #define BUFFER_PADDING_SIZE 20
 
 /** End platform defines **/