diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index f43a127..a413877 100755
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -15,7 +15,8 @@ if [[ $DOCKER_HOST = unix://* ]]; then
 fi
 
 # Generate dhparam file if required
-/app/generate-dhparam.sh
+# Note: if $DHPARAM_BITS is not defined, generate-dhparam.sh will use 2048 as a default
+/app/generate-dhparam.sh $DHPARAM_BITS
 
 # If the user has run the default command and the socket doesn't exist, fail
 if [ "$socketMissing" = 1 -a "$1" = forego -a "$2" = start -a "$3" = '-r' ]; then
diff --git a/generate-dhparam.sh b/generate-dhparam.sh
index 0097754..9f5d4ff 100755
--- a/generate-dhparam.sh
+++ b/generate-dhparam.sh
@@ -1,10 +1,12 @@
 #!/bin/bash -e
 
+# The first argument is the bit depth of the dhparam, or 2048 if unspecified
+DHPARAM_BITS=${1:-2048}
+
 # If a dhparam file is not available, use the pre-generated one and generate a new one in the background.
 # Note that /etc/nginx/dhparam is a volume, so this dhparam will persist restarts.
 PREGEN_DHPARAM_FILE="/app/dhparam.pem.default"
 DHPARAM_FILE="/etc/nginx/dhparam/dhparam.pem"
-DHPARAM_BITS="2048"
 GEN_LOCKFILE="/tmp/dhparam_generating.lock"
 
 # The hash of the pregenerated dhparam file is used to check if the pregen dhparam is already in use
diff --git a/test/ssl_dhparam.bats b/test/ssl_dhparam.bats
index c5470a6..c193c5c 100644
--- a/test/ssl_dhparam.bats
+++ b/test/ssl_dhparam.bats
@@ -7,7 +7,7 @@ function setup {
 	stop_bats_containers web
 }
 
-@test "[$TEST_FILE] test dhparam.pem is generated if missing (WARNING: this test is slow)" {
+@test "[$TEST_FILE] test dhparam.pem is generated if missing" {
     SUT_CONTAINER=bats-nginx-proxy-${TEST_FILE}-1
 
     # WHEN
@@ -16,6 +16,7 @@ function setup {
         --label bats-type="nginx-proxy" \
         --name $SUT_CONTAINER \
         -v /var/run/docker.sock:/tmp/docker.sock:ro \
+        -e DHPARAM=256 \
         $SUT_IMAGE \
     && wait_for_nginxproxy_container_to_start $SUT_CONTAINER \
     && docker logs $SUT_CONTAINER
@@ -23,7 +24,7 @@ function setup {
     DEFAULT_HASH=$(docker exec $SUT_CONTAINER md5sum /etc/nginx/dhparam/dhparam.pem | cut -d" " -f1)
 
     assert_success
-    docker_wait_for_log $SUT_CONTAINER 9 "Generating DH parameters"
+    docker_wait_for_log $SUT_CONTAINER 30 "Generating DH parameters"
 
     # THEN
     docker_wait_for_log $SUT_CONTAINER 240 "dhparam generation complete, reloading nginx"
@@ -56,13 +57,14 @@ function setup {
 		--name $SUT_CONTAINER \
 		-v /var/run/docker.sock:/tmp/docker.sock:ro \
 		-v $TMP_DIR:/etc/nginx/dhparam \
+        -e DHPARAM=256 \
 		$SUT_IMAGE \
 	&& wait_for_nginxproxy_container_to_start $SUT_CONTAINER \
 	&& docker logs $SUT_CONTAINER
 
 	# THEN
 	assert_success
-	docker_wait_for_log $SUT_CONTAINER 9 "Generating DH parameters"
+	docker_wait_for_log $SUT_CONTAINER 30 "Generating DH parameters"
 
 	docker exec $SUT_CONTAINER rm -rf /etc/nginx/dhparam/*
 }