diff --git a/utbot-framework/src/main/kotlin/org/utbot/engine/ValueConstructor.kt b/utbot-framework/src/main/kotlin/org/utbot/engine/ValueConstructor.kt
index 93c1122802..06928beda1 100644
--- a/utbot-framework/src/main/kotlin/org/utbot/engine/ValueConstructor.kt
+++ b/utbot-framework/src/main/kotlin/org/utbot/engine/ValueConstructor.kt
@@ -3,6 +3,7 @@ package org.utbot.engine
 import org.utbot.common.findField
 import org.utbot.common.findFieldOrNull
 import org.utbot.common.invokeCatching
+import org.utbot.common.withAccessibility
 import org.utbot.framework.plugin.api.ClassId
 import org.utbot.framework.plugin.api.ConstructorId
 import org.utbot.framework.plugin.api.EnvironmentModels
@@ -390,12 +391,19 @@ class ValueConstructor {
      */
     private fun value(model: UtModel) = construct(model, null).value
 
-
     private fun MethodId.call(args: List<Any?>, instance: Any?): Any? =
-        method.invokeCatching(obj = instance, args = args).getOrThrow()
+        method.run {
+            withAccessibility {
+                invokeCatching(obj = instance, args = args).getOrThrow()
+            }
+        }
 
     private fun ConstructorId.call(args: List<Any?>): Any? =
-        constructor.newInstance(*args.toTypedArray())
+        constructor.run {
+            withAccessibility {
+                newInstance(*args.toTypedArray())
+            }
+        }
 
     /**
      * Fetches primitive value from NutsModel to create array of primitives.
diff --git a/utbot-framework/src/main/kotlin/org/utbot/framework/assemble/AssembleModelGenerator.kt b/utbot-framework/src/main/kotlin/org/utbot/framework/assemble/AssembleModelGenerator.kt
index ce2f389c39..1842f652c6 100644
--- a/utbot-framework/src/main/kotlin/org/utbot/framework/assemble/AssembleModelGenerator.kt
+++ b/utbot-framework/src/main/kotlin/org/utbot/framework/assemble/AssembleModelGenerator.kt
@@ -38,6 +38,7 @@ import org.utbot.framework.plugin.api.util.defaultValueModel
 import org.utbot.framework.plugin.api.util.executableId
 import org.utbot.framework.plugin.api.util.jClass
 import org.utbot.framework.util.nextModelName
+import java.lang.reflect.Constructor
 import java.util.IdentityHashMap
 
 /**
@@ -256,7 +257,7 @@ class AssembleModelGenerator(private val methodUnderTest: UtMethod<*>) {
                     }
                     //fill field value if it hasn't been filled by constructor, and it is not default
                     if (fieldId in constructorInfo.affectedFields ||
-                        (fieldId !in constructorInfo.setFields && !fieldModel.hasDefaultValue())
+                            (fieldId !in constructorInfo.setFields && !fieldModel.hasDefaultValue())
                     ) {
                         val modifierCall = modifierCall(this, fieldId, assembleModel(fieldModel))
                         callChain.add(modifierCall)
@@ -357,15 +358,21 @@ class AssembleModelGenerator(private val methodUnderTest: UtMethod<*>) {
      */
     private fun findBestConstructorOrNull(compositeModel: UtCompositeModel): ConstructorId? {
         val classId = compositeModel.classId
-        if (!classId.isPublic || classId.isInner) return null
+        if (!classId.isVisible || classId.isInner) return null
 
         return classId.jClass.declaredConstructors
-            .filter { it.isPublic || !it.isPrivate && it.declaringClass.packageName.startsWith(methodPackageName) }
+            .filter { it.isVisible }
             .sortedByDescending { it.parameterCount }
             .map { it.executableId }
             .firstOrNull { constructorAnalyzer.isAppropriate(it) }
     }
 
+    private val ClassId.isVisible : Boolean
+        get() = this.isPublic || !this.isPrivate && this.packageName.startsWith(methodPackageName)
+
+    private val Constructor<*>.isVisible : Boolean
+        get() = this.isPublic || !this.isPrivate && this.declaringClass.packageName.startsWith(methodPackageName)
+
     /**
      * Creates setter or direct setter call to set a field.
      *
diff --git a/utbot-framework/src/main/kotlin/org/utbot/framework/concrete/MockValueConstructor.kt b/utbot-framework/src/main/kotlin/org/utbot/framework/concrete/MockValueConstructor.kt
index 4fa9d34071..d1452b2cef 100644
--- a/utbot-framework/src/main/kotlin/org/utbot/framework/concrete/MockValueConstructor.kt
+++ b/utbot-framework/src/main/kotlin/org/utbot/framework/concrete/MockValueConstructor.kt
@@ -45,6 +45,7 @@ import kotlin.reflect.KClass
 import org.mockito.Mockito
 import org.mockito.stubbing.Answer
 import org.objectweb.asm.Type
+import org.utbot.common.withAccessibility
 
 /**
  * Constructs values (including mocks) from models.
@@ -433,10 +434,18 @@ class MockValueConstructor(
     }
 
     private fun MethodId.call(args: List<Any?>, instance: Any?): Any? =
-        method.invokeCatching(obj = instance, args = args).getOrThrow()
+        method.run {
+            withAccessibility {
+                invokeCatching(obj = instance, args = args).getOrThrow()
+            }
+        }
 
     private fun ConstructorId.call(args: List<Any?>): Any? =
-        constructor.newInstance(*args.toTypedArray())
+        constructor.run {
+            withAccessibility {
+                newInstance(*args.toTypedArray())
+            }
+        }
 
     /**
      * Fetches primitive value from NutsModel to create array of primitives.