diff --git a/daemon/lua/kres-gen.lua b/daemon/lua/kres-gen.lua
index 7f687c6fcd68bad08a6498618de914b92840fbde..6e2011b9fee943ee4c2643f200d44abef39dc863 100644
--- a/daemon/lua/kres-gen.lua
+++ b/daemon/lua/kres-gen.lua
@@ -318,6 +318,7 @@ uint64_t kr_now();
 void lru_free_items_impl(struct lru *);
 struct lru *lru_create_impl(unsigned int, knot_mm_t *, knot_mm_t *);
 void *lru_get_impl(struct lru *, const char *, unsigned int, unsigned int, _Bool, _Bool *);
+void *mm_realloc(knot_mm_t *, void *, size_t, size_t);
 knot_rrset_t *kr_ta_get(map_t *, const knot_dname_t *);
 int kr_ta_add(map_t *, const knot_dname_t *, uint16_t, uint32_t, const uint8_t *, uint16_t);
 int kr_ta_del(map_t *, const knot_dname_t *);
diff --git a/daemon/lua/kres-gen.sh b/daemon/lua/kres-gen.sh
index 73e16b46caedf3c7d0d64c1588b4f82410370750..9b06a15624ab8a7a6c944ec8b8ec33b6cd75da27 100755
--- a/daemon/lua/kres-gen.sh
+++ b/daemon/lua/kres-gen.sh
@@ -172,6 +172,7 @@ EOF
 	lru_free_items_impl
 	lru_create_impl
 	lru_get_impl
+	mm_realloc
 # Trust anchors
 	kr_ta_get
 	kr_ta_add
diff --git a/daemon/lua/kres.lua b/daemon/lua/kres.lua
index 4eeb0da581f4252cdcb770900f46f74cd8af7a14..4a63c704805870bd3e5ab988e892c08c813fee36 100644
--- a/daemon/lua/kres.lua
+++ b/daemon/lua/kres.lua
@@ -696,6 +696,15 @@ ffi.metatype( knot_pkt_t, {
 			if ret ~= 0 then return nil, knot_error_t(ret) end
 			return true
 		end,
+		-- Resize packet wire to a new size
+		resize = function (pkt, new_size)
+			assert(ffi.istype(knot_pkt_t, pkt))
+			local ptr = C.mm_realloc(pkt.mm, pkt.wire, new_size, pkt.max_size)
+			if ptr == nil then return end
+			pkt.wire = ptr
+			pkt.max_size = new_size
+			return true
+		end,
 	},
 })
 -- Metatype for query
diff --git a/lib/utils.c b/lib/utils.c
index 9a7a69e6fbc0ead82644a6b7fdc0976459cb991a..b818aefa96349cf9d3225bd275415a60068ef715 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -53,6 +53,24 @@ static isaac_ctx ISAAC;
 static bool isaac_seeded = false;
 #define SEED_SIZE 256
 
+void *mm_realloc(knot_mm_t *mm, void *what, size_t size, size_t prev_size)
+{
+	if (mm) {
+		void *p = mm->alloc(mm->ctx, size);
+		if (p == NULL) {
+			return NULL;
+		} else {
+			if (what) {
+				memcpy(p, what,
+				       prev_size < size ? prev_size : size);
+			}
+			mm_free(mm, what);
+			return p;
+		}
+	} else {
+		return realloc(what, size);
+	}
+}
 
 void *mm_malloc(void *ctx, size_t n)
 {
diff --git a/lib/utils.h b/lib/utils.h
index b61b4f76c39e59f1ea73ef1ab312841a397310ca..7d517898df9dcca7d3c97d0bcf5fe206fe18d24a 100644
--- a/lib/utils.h
+++ b/lib/utils.h
@@ -111,24 +111,10 @@ static inline void mm_free(knot_mm_t *mm, const void *what)
 	}
 	else free((void *)what);
 }
-static inline void *mm_realloc(knot_mm_t *mm, void *what, size_t size, size_t prev_size)
-{
-	if (mm) {
-		void *p = mm->alloc(mm->ctx, size);
-		if (p == NULL) {
-			return NULL;
-		} else {
-			if (what) {
-				memcpy(p, what,
-				       prev_size < size ? prev_size : size);
-			}
-			mm_free(mm, what);
-			return p;
-		}
-	} else {
-		return realloc(what, size);
-	}
-}
+
+/** Realloc implementation using memory context. */
+KR_EXPORT
+void *mm_realloc(knot_mm_t *mm, void *what, size_t size, size_t prev_size);
 
 /** Trivial malloc() wrapper. */
 void *mm_malloc(void *ctx, size_t n);
diff --git a/tests/config/basic.test.lua b/tests/config/basic.test.lua
index 7667ebab1f3891580d74c47ab5288ee9b9bfa24a..520f63e0d48e8c2c98052d1114c832a32dc7b0bb 100644
--- a/tests/config/basic.test.lua
+++ b/tests/config/basic.test.lua
@@ -99,7 +99,7 @@ local function test_packet_functions()
 	-- Test manipulating sections
 	ok(pkt:begin(kres.section.ANSWER), 'switching sections works')
 	local res, err = pkt:put(nil, 0, 0, 0, '')
-	isnt(res, 'inserting nil entry doesnt work')
+	isnt(res, true, 'inserting nil entry doesnt work')
 	isnt(err.code, 0, 'error code is non-zero')
 	isnt(tostring(res), '', 'inserting nil returns invalid parameter')
 	ok(pkt:put(pkt:qname(), 900, pkt:qclass(), kres.type.A, '\1\2\3\4'), 'adding rrsets works')
@@ -131,13 +131,15 @@ local function test_packet_functions()
 	same(parsed:tostring(), pkt:tostring(), 'parsed packet is equal to source packet')
 
 	-- Test adding RR sets directly
-	local copy = kres.packet(512)
+	local copy = kres.packet(23)
 	copy:question(todname('hello'), kres.class.IN, kres.type.A)
 	copy:begin(kres.section.ANSWER)
 	local rr = kres.rrset(pkt:qname(), kres.type.A, kres.class.IN, 66)
 	rr:add_rdata('\4\3\2\1', 4)
+	ok(not copy:put_rr(rr), 'adding RR sets checks for available space')
+	ok(copy:resize(512), 'resizing packet works')
 	ok(copy:put_rr(rr), 'adding RR sets directly works')
-	ok(copy:recycle())
+	ok(copy:recycle(), 'recycling packet works')
 
 	-- Test recycling of packets
 	-- Clear_payload keeps header + question intact