diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
index 1c2c39b2e27..26c6742e8b1 100644
--- a/src/backend/utils/adt/datetime.c
+++ b/src/backend/utils/adt/datetime.c
@@ -2873,19 +2873,18 @@ DecodeInterval(char **field, int *ftype, int nf, int range,
 			case DTK_TZ:
 
 				/*
-				 * Timezone is a token with a leading sign character and at
+				 * Timezone means a token with a leading sign character and at
 				 * least one digit; there could be ':', '.', '-' embedded in
 				 * it as well.
 				 */
 				Assert(*field[i] == '-' || *field[i] == '+');
 
 				/*
-				 * Try for hh:mm or hh:mm:ss.  If not, fall through to
-				 * DTK_NUMBER case, which can handle signed float numbers and
-				 * signed year-month values.
+				 * Check for signed hh:mm or hh:mm:ss.  If so, process exactly
+				 * like DTK_TIME case above, plus handling the sign.
 				 */
 				if (strchr(field[i] + 1, ':') != NULL &&
-					DecodeTime(field[i] + 1, fmask, INTERVAL_FULL_RANGE,
+					DecodeTime(field[i] + 1, fmask, range,
 							   &tmask, tm, fsec) == 0)
 				{
 					if (*field[i] == '-')
@@ -2903,9 +2902,14 @@ DecodeInterval(char **field, int *ftype, int nf, int range,
 					 * are reading right to left.
 					 */
 					type = DTK_DAY;
-					tmask = DTK_M(TZ);
 					break;
 				}
+
+				/*
+				 * Otherwise, fall through to DTK_NUMBER case, which can
+				 * handle signed float numbers and signed year-month values.
+				 */
+
 				/* FALL THROUGH */
 
 			case DTK_DATE:
diff --git a/src/test/regress/expected/interval.out b/src/test/regress/expected/interval.out
index e7e21813332..3bf221187bc 100644
--- a/src/test/regress/expected/interval.out
+++ b/src/test/regress/expected/interval.out
@@ -545,6 +545,30 @@ SELECT interval '1 2:03:04' minute to second;
  1 day 02:03:04
 (1 row)
 
+SELECT interval '1 +2:03' minute to second;
+    interval    
+----------------
+ 1 day 00:02:03
+(1 row)
+
+SELECT interval '1 +2:03:04' minute to second;
+    interval    
+----------------
+ 1 day 02:03:04
+(1 row)
+
+SELECT interval '1 -2:03' minute to second;
+    interval     
+-----------------
+ 1 day -00:02:03
+(1 row)
+
+SELECT interval '1 -2:03:04' minute to second;
+    interval     
+-----------------
+ 1 day -02:03:04
+(1 row)
+
 SELECT interval '123 11' day to hour; -- ok
      interval      
 -------------------
@@ -559,6 +583,10 @@ SELECT interval '123 11'; -- not ok, too ambiguous
 ERROR:  invalid input syntax for type interval: "123 11"
 LINE 1: SELECT interval '123 11';
                         ^
+SELECT interval '123 2:03 -2:04'; -- not ok, redundant hh:mm fields
+ERROR:  invalid input syntax for type interval: "123 2:03 -2:04"
+LINE 1: SELECT interval '123 2:03 -2:04';
+                        ^
 -- test syntaxes for restricted precision
 SELECT interval(0) '1 day 01:23:45.6789';
     interval    
diff --git a/src/test/regress/sql/interval.sql b/src/test/regress/sql/interval.sql
index 9da2dc63e87..f1da4c29117 100644
--- a/src/test/regress/sql/interval.sql
+++ b/src/test/regress/sql/interval.sql
@@ -165,9 +165,14 @@ SELECT interval '1 2:03:04' hour to second;
 SELECT interval '1 2' minute to second;
 SELECT interval '1 2:03' minute to second;
 SELECT interval '1 2:03:04' minute to second;
+SELECT interval '1 +2:03' minute to second;
+SELECT interval '1 +2:03:04' minute to second;
+SELECT interval '1 -2:03' minute to second;
+SELECT interval '1 -2:03:04' minute to second;
 SELECT interval '123 11' day to hour; -- ok
 SELECT interval '123 11' day; -- not ok
 SELECT interval '123 11'; -- not ok, too ambiguous
+SELECT interval '123 2:03 -2:04'; -- not ok, redundant hh:mm fields
 
 -- test syntaxes for restricted precision
 SELECT interval(0) '1 day 01:23:45.6789';