diff --git a/modules/nextflow/build.gradle b/modules/nextflow/build.gradle
index a71409a676..dd735887c4 100644
--- a/modules/nextflow/build.gradle
+++ b/modules/nextflow/build.gradle
@@ -61,8 +61,8 @@ dependencies {
     testFixturesApi ("org.apache.groovy:groovy-test:4.0.29") { exclude group: 'org.apache.groovy' }
     testFixturesApi ("org.objenesis:objenesis:3.4")
     testFixturesApi ("net.bytebuddy:byte-buddy:1.14.17")
-    testFixturesApi ("org.spockframework:spock-core:2.3-groovy-4.0") { exclude group: 'org.apache.groovy' }
-    testFixturesApi ('org.spockframework:spock-junit4:2.3-groovy-4.0') { exclude group: 'org.apache.groovy' }
+    testFixturesApi ("org.spockframework:spock-core:2.4-groovy-4.0") { exclude group: 'org.apache.groovy' }
+    testFixturesApi ('org.spockframework:spock-junit4:2.4-groovy-4.0') { exclude group: 'org.apache.groovy' }
     testFixturesApi 'com.google.jimfs:jimfs:1.2'
     // note: declare as separate dependency to avoid a circular dependency
     lineageImplementation (project(':nf-lineage'))
diff --git a/modules/nextflow/src/test/groovy/nextflow/processor/TaskRunTest.groovy b/modules/nextflow/src/test/groovy/nextflow/processor/TaskRunTest.groovy
index 6cfee6bbc0..e057a80e29 100644
--- a/modules/nextflow/src/test/groovy/nextflow/processor/TaskRunTest.groovy
+++ b/modules/nextflow/src/test/groovy/nextflow/processor/TaskRunTest.groovy
@@ -882,11 +882,13 @@ class TaskRunTest extends Specification {
         !task.isArray()
     }
 
+    // note: use `stubRun >> value` instead of `getStubRun() >> value` because
+    // Spock 2.4 requires property stubbing for direct property access (session.stubRun)
     def 'should resolve task body' () {
         given:
         def task = Spy(TaskRun)
         task.processor = Mock(TaskProcessor) {
-            getSession()>>Mock(Session) { getStubRun() >> false}
+            getSession()>>Mock(Session) { stubRun >> false}
         }
         and:
         def body = Mock(BodyDef)
@@ -902,7 +904,7 @@ class TaskRunTest extends Specification {
         given:
         def task = Spy(TaskRun)
         task.processor = Mock(TaskProcessor) {
-            getSession()>>Mock(Session) { getStubRun() >> true}
+            getSession()>>Mock(Session) { stubRun >> true}
         }
         task.config = Mock(TaskConfig) { getStubBlock()>> null }
         and:
@@ -923,7 +925,7 @@ class TaskRunTest extends Specification {
         def task = Spy(TaskRun)
         task.config = Mock(TaskConfig) { getStubBlock()>>stub }
         task.processor = Mock(TaskProcessor) {
-            getSession()>>Mock(Session) { getStubRun() >> true}
+            getSession()>>Mock(Session) { stubRun >> true}
         }
 
         when: