diff --git a/garden-service/src/plugins/container/helpers.ts b/garden-service/src/plugins/container/helpers.ts
index ff6ad44616..2c79407ef1 100644
--- a/garden-service/src/plugins/container/helpers.ts
+++ b/garden-service/src/plugins/container/helpers.ts
@@ -11,7 +11,7 @@ import { join } from "path"
 import { ConfigurationError } from "../../exceptions"
 import { splitFirst, spawn } from "../../util/util"
 import { ModuleConfig } from "../../config/module"
-import { ContainerModule, ContainerRegistryConfig, defaultTag } from "./config"
+import { ContainerModule, ContainerRegistryConfig, defaultTag, defaultNamespace } from "./config"
 
 interface ParsedImageId {
   host?: string
@@ -101,15 +101,16 @@ export const containerHelpers = {
   },
 
   parseImageId(imageId: string): ParsedImageId {
-    const parts = imageId.split("/")
-    let [repository, tag] = parts[0].split(":")
+    let [name, tag] = imageId.split(":")
+    const parts = name.length > 0 ? name.split("/") : []
+
     if (!tag) {
       tag = defaultTag
     }
 
     if (parts.length === 1) {
       return {
-        repository,
+        repository: parts[0],
         tag,
       }
     } else if (parts.length === 2) {
@@ -141,7 +142,7 @@ export const containerHelpers = {
     const name = `${parsed.repository}:${parsed.tag}`
 
     if (parsed.host) {
-      return `${parsed.host}/${parsed.namespace}/${name}`
+      return `${parsed.host}/${parsed.namespace || defaultNamespace}/${name}`
     } else if (parsed.namespace) {
       return `${parsed.namespace}/${name}`
     } else {
diff --git a/garden-service/test/src/plugins/container.ts b/garden-service/test/src/plugins/container.ts
index ecd7ec8d2a..6bed534d1b 100644
--- a/garden-service/test/src/plugins/container.ts
+++ b/garden-service/test/src/plugins/container.ts
@@ -210,6 +210,92 @@ describe("plugins.container", () => {
     })
   })
 
+  describe("parseImageId", () => {
+    it("should correctly parse a simple id", () => {
+      expect(containerHelpers.parseImageId("image:tag")).to.eql({
+        repository: "image",
+        tag: "tag",
+      })
+    })
+
+    it("should correctly parse an id with a namespace", () => {
+      expect(containerHelpers.parseImageId("namespace/image:tag")).to.eql({
+        namespace: "namespace",
+        repository: "image",
+        tag: "tag",
+      })
+    })
+
+    it("should correctly parse an id with a host and namespace", () => {
+      expect(containerHelpers.parseImageId("my-host.com/namespace/image:tag")).to.eql({
+        host: "my-host.com",
+        namespace: "namespace",
+        repository: "image",
+        tag: "tag",
+      })
+    })
+
+    it("should correctly parse an id with a host and multi-level namespace", () => {
+      expect(containerHelpers.parseImageId("my-host.com/a/b/c/d/image:tag")).to.eql({
+        host: "my-host.com",
+        namespace: "a/b/c/d",
+        repository: "image",
+        tag: "tag",
+      })
+    })
+
+    it("should throw on an empty name", async () => {
+      await expectError(() => containerHelpers.parseImageId(""), "configuration")
+    })
+  })
+
+  describe("unparseImageId", () => {
+    it("should correctly compose a simple id", () => {
+      expect(containerHelpers.unparseImageId({
+        repository: "image",
+        tag: "tag",
+      })).to.equal("image:tag")
+    })
+
+    it("should correctly compose an id with a namespace", () => {
+      expect(containerHelpers.unparseImageId({
+        namespace: "namespace",
+        repository: "image",
+        tag: "tag",
+      })).to.equal("namespace/image:tag")
+    })
+
+    it("should correctly compose an id with a host and namespace", () => {
+      expect(containerHelpers.unparseImageId({
+        host: "my-host.com",
+        namespace: "namespace",
+        repository: "image",
+        tag: "tag",
+      })).to.equal("my-host.com/namespace/image:tag")
+    })
+
+    it("should set a default namespace when host but no namespace is specified", () => {
+      expect(containerHelpers.unparseImageId({
+        host: "my-host.com",
+        repository: "image",
+        tag: "tag",
+      })).to.equal("my-host.com/_/image:tag")
+    })
+
+    it("should correctly compose an id with a host and multi-level namespace", () => {
+      expect(containerHelpers.unparseImageId({
+        host: "my-host.com",
+        namespace: "a/b/c/d",
+        repository: "image",
+        tag: "tag",
+      })).to.equal("my-host.com/a/b/c/d/image:tag")
+    })
+
+    it("should throw on an empty name", async () => {
+      await expectError(() => containerHelpers.parseImageId(""), "configuration")
+    })
+  })
+
   describe("DockerModuleHandler", () => {
     describe("validate", () => {
       it("should validate and parse a container module", async () => {