diff --git a/src/util/longbits.js b/src/util/longbits.js
index 305437152..64aaa6332 100644
--- a/src/util/longbits.js
+++ b/src/util/longbits.js
@@ -67,13 +67,23 @@ LongBits.fromNumber = function fromNumber(value) {
 
 /**
  * Constrcuts new long bits from a number or long.
- * @param {Long|number} value Value
+ * @param {Long|number|string} value Value
  * @returns {util.LongBits} Instance
  */
 LongBits.from = function from(value) {
-    return typeof value === 'number'
-        ? LongBits.fromNumber(value)
-        : new LongBits(value.low >>> 0, value.high >>> 0);
+    var type = typeof value, result=zero;
+    if(type === 'number')
+        result = LongBits.fromNumber(value);
+    else 
+    {
+        if(type === 'string' && util.Long)
+            value = util.Long.fromString(value);
+    
+        if(value.low || value.high)
+            result = new LongBits(value.low >>> 0, value.high >>> 0);
+    }
+        
+    return result;
 };
 
 /**
diff --git a/src/writer.js b/src/writer.js
index 65c4a0fe6..645e47ec3 100644
--- a/src/writer.js
+++ b/src/writer.js
@@ -214,31 +214,25 @@ function writeVarint64(buf, pos, val) {
 
 /**
  * Writes an unsigned 64 bit value as a varint.
- * @param {Long|number} value Value to write
+ * @param {Long|number|string} value Value to write
  * @returns {Writer} `this`
  */
 WriterPrototype.uint64 = function write_uint64(value) {
-    var bits;
-    if (typeof value === 'number')
-        bits = value ? LongBits.fromNumber(value) : LongBits.zero;
-    else if (value.low || value.high)
-        bits = new LongBits(value.low >>> 0, value.high >>> 0);
-    else
-        bits = LongBits.zero;
+    var bits = LongBits.from(value);
     return this.push(writeVarint64, bits.length(), bits);
 };
 
 /**
  * Writes a signed 64 bit value as a varint.
  * @function
- * @param {Long|number} value Value to write
+ * @param {Long|number|string} value Value to write
  * @returns {Writer} `this`
  */
 WriterPrototype.int64 = WriterPrototype.uint64;
 
 /**
  * Writes a signed 64 bit value as a varint, zig-zag encoded.
- * @param {Long|number} value Value to write
+ * @param {Long|number|string} value Value to write
  * @returns {Writer} `this`
  */
 WriterPrototype.sint64 = function sint64(value) {
@@ -246,6 +240,7 @@ WriterPrototype.sint64 = function sint64(value) {
     return this.push(writeVarint64, bits.length(), bits);
 };
 
+
 /**
  * Writes a boolish value as a varint.
  * @param {boolean} value Value to write