diff --git a/driver/src/main/java/org/neo4j/driver/internal/InternalIsoDuration.java b/driver/src/main/java/org/neo4j/driver/internal/InternalIsoDuration.java
index 8dd8761fac..d3f7dceb64 100644
--- a/driver/src/main/java/org/neo4j/driver/internal/InternalIsoDuration.java
+++ b/driver/src/main/java/org/neo4j/driver/internal/InternalIsoDuration.java
@@ -38,8 +38,6 @@
 public class InternalIsoDuration implements IsoDuration
 {
     private static final List<TemporalUnit> SUPPORTED_UNITS = unmodifiableList( asList( MONTHS, DAYS, SECONDS, NANOS ) );
-    private static final InternalIsoDuration ZERO = new InternalIsoDuration( 0, 0, 0, 0 );
-    public static final long NANOS_PER_SECOND = 1_000_000_000L;
 
     private final long months;
     private final long days;
@@ -195,65 +193,6 @@ public int hashCode()
     @Override
     public String toString()
     {
-        // print the duration in iso standard format.
-        if ( this.equals( ZERO ) )
-        {
-            return "PT0S"; // no need to allocate a string builder if we know the result
-        }
-        StringBuilder str = new StringBuilder().append( "P" );
-        append( str, months / 12, 'Y' );
-        append( str, months % 12, 'M' );
-        append( str, days / 7, 'W' );
-        append( str, days % 7, 'D' );
-        if ( seconds != 0 || nanoseconds != 0 )
-        {
-            str.append( 'T' );
-            long s = seconds % 3600;
-            append( str, seconds / 3600, 'H' );
-            append( str, s / 60, 'M' );
-            s %= 60;
-            if ( s != 0 )
-            {
-                str.append( s );
-                if ( nanoseconds != 0 )
-                {
-                    nanos( str );
-                }
-                str.append( 'S' );
-            }
-            else if ( nanoseconds != 0 )
-            {
-                if ( nanoseconds < 0 )
-                {
-                    str.append( '-' );
-                }
-                str.append( '0' );
-                nanos( str );
-                str.append( 'S' );
-            }
-        }
-        if ( str.length() == 1 )
-        { // this was all zeros (but not ZERO for some reason), ensure well formed output:
-            str.append( "T0S" );
-        }
-        return str.toString();
-    }
-
-    private static void append( StringBuilder str, long quantity, char unit )
-    {
-        if ( quantity != 0 )
-        {
-            str.append( quantity ).append( unit );
-        }
-    }
-
-    private void nanos( StringBuilder str )
-    {
-        str.append( '.' );
-        int n = nanoseconds < 0 ? -nanoseconds : nanoseconds;
-        for ( int mod = (int)NANOS_PER_SECOND; mod > 1 && n > 0; n %= mod )
-        {
-            str.append( n / (mod /= 10) );
-        }
+        return String.format( "P%sM%sDT%s.%sS", months, days, seconds, String.format( "%09d", nanoseconds ) );
     }
 }
diff --git a/driver/src/test/java/org/neo4j/driver/internal/InternalIsoDurationTest.java b/driver/src/test/java/org/neo4j/driver/internal/InternalIsoDurationTest.java
index 506b247780..9a9aa13e24 100644
--- a/driver/src/test/java/org/neo4j/driver/internal/InternalIsoDurationTest.java
+++ b/driver/src/test/java/org/neo4j/driver/internal/InternalIsoDurationTest.java
@@ -156,13 +156,17 @@ public void shouldCreateFromDuration()
     @Test
     public void toStringShouldPrintInIsoStandardFormat() throws Throwable
     {
-        assertThat( new InternalIsoDuration( 0, 0, 0, 0 ).toString(), equalTo( "PT0S" ) );
-        assertThat( new InternalIsoDuration( Period.parse( "P356D" ) ).toString(), equalTo( "P50W6D" ) );
-        assertThat( new InternalIsoDuration( Duration.parse( "PT45S" ) ).toString(), equalTo( "PT45S" ) );
+        assertThat( new InternalIsoDuration( 0, 0, 0, 0 ).toString(), equalTo( "P0M0DT0.000000000S" ) );
+        assertThat( new InternalIsoDuration( 2, 45, 59, 11 ).toString(), equalTo( "P2M45DT59.000000011S" ) );
+        assertThat( new InternalIsoDuration( 4, -101, 1, 999 ).toString(), equalTo( "P4M-101DT1.000000999S" ) );
+        assertThat( new InternalIsoDuration( -1, 12, -19, 1 ).toString(), equalTo( "P-1M12DT-19.000000001S" ) );
 
-        assertThat( new InternalIsoDuration( Period.parse( "P14D" ), Duration.parse( "PT16H12M" ) ).toString(), equalTo( "P2WT16H12M" ) );
-        assertThat( new InternalIsoDuration( Period.parse( "P5M1D" ), Duration.parse( "PT12H" ) ).toString(), equalTo( "P5M1DT12H" ) );
-        assertThat( new InternalIsoDuration( Period.parse( "P2W3D" ), Duration.parse( "PT12H" ) ).toString(), equalTo( "P2W3DT12H" ) );
+        assertThat( new InternalIsoDuration( Period.parse( "P356D" ) ).toString(), equalTo( "P0M356DT0.000000000S" ) );
+        assertThat( new InternalIsoDuration( Duration.parse( "PT45S" ) ).toString(), equalTo( "P0M0DT45.000000000S" ) );
+
+        assertThat( new InternalIsoDuration( Period.parse( "P14D" ), Duration.parse( "PT16H12M" ) ).toString(), equalTo( "P0M14DT58320.000000000S" ) );
+        assertThat( new InternalIsoDuration( Period.parse( "P5M1D" ), Duration.parse( "PT12H" ) ).toString(), equalTo( "P5M1DT43200.000000000S" ) );
+        assertThat( new InternalIsoDuration( Period.parse( "P2W3D" ), Duration.parse( "PT2H0.111222333S" ) ).toString(), equalTo( "P0M17DT7200.111222333S" ) );
     }
 
     private static IsoDuration newDuration( long months, long days, long seconds, int nanoseconds )