diff --git a/utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/conntrack.lua b/utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/conntrack.lua
index 93b26c266..1abb7a191 100644
--- a/utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/conntrack.lua
+++ b/utils/prometheus-node-exporter-lua/files/usr/lib/lua/prometheus-collectors/conntrack.lua
@@ -1,8 +1,12 @@
 local function scrape()
-  metric("node_nf_conntrack_entries", "gauge", nil,
-    string.sub(get_contents("/proc/sys/net/netfilter/nf_conntrack_count"), 1, -2))
-  metric("node_nf_conntrack_entries_limit", "gauge", nil,
-    string.sub(get_contents("/proc/sys/net/netfilter/nf_conntrack_max"), 1, -2))
+  local count = get_contents("/proc/sys/net/netfilter/nf_conntrack_count")
+  local max = get_contents("/proc/sys/net/netfilter/nf_conntrack_max")
+  if count ~= "" then
+    metric("node_nf_conntrack_entries", "gauge", nil, string.sub(count, 1, -2))
+  end
+  if max ~= "" then
+    metric("node_nf_conntrack_entries_limit", "gauge", nil, string.sub(max, 1, -2))
+  end
 end
 
 return { scrape = scrape }