diff --git a/tests/waku_rln_relay/test_rln_group_manager_onchain.nim b/tests/waku_rln_relay/test_rln_group_manager_onchain.nim
index cf697961a4..7750efad2b 100644
--- a/tests/waku_rln_relay/test_rln_group_manager_onchain.nim
+++ b/tests/waku_rln_relay/test_rln_group_manager_onchain.nim
@@ -436,3 +436,26 @@ suite "Onchain group manager":
 
     check:
       isReady == true
+
+  test "register: should use max gas price when useMaxGasPrice flag is set":
+    (waitFor manager.init()).isOkOr:
+      raiseAssert $error
+
+    manager.useMaxGasPrice = true
+
+    let idCredentials = generateCredentials()
+    let merkleRootBefore = waitFor manager.fetchMerkleRoot()
+
+    try:
+      waitFor manager.register(idCredentials, UserMessageLimit(20))
+    except Exception, CatchableError:
+      assert false,
+        "exception raised when calling register with useMaxGasPrice: " &
+          getCurrentExceptionMsg()
+
+    let merkleRootAfter = waitFor manager.fetchMerkleRoot()
+
+    check:
+      merkleRootAfter != merkleRootBefore
+      manager.latestIndex == 1
+      manager.useMaxGasPrice == true
diff --git a/tools/confutils/cli_args.nim b/tools/confutils/cli_args.nim
index fb84372993..4ad9310563 100644
--- a/tools/confutils/cli_args.nim
+++ b/tools/confutils/cli_args.nim
@@ -138,6 +138,13 @@ type WakuNodeConf* = object
       defaultValue: false,
       name: "execute"
     .}: bool
+
+    rlnRelayMaxGasPrice* {.
+      desc:
+        "Use fixed large gas price (1000 Gwei) for the registration transaction. If not set, will use 2x current gas price.",
+      defaultValue: false,
+      name: "rln-relay-max-gas-price"
+    .}: bool
   of noCommand:
     ##  Application-level configuration
     protectedShards* {.
@@ -885,6 +892,7 @@ proc toKeystoreGeneratorConf*(n: WakuNodeConf): RlnKeystoreGeneratorConf =
     ethPrivateKey: n.rlnRelayEthPrivateKey,
     credPath: n.rlnRelayCredPath,
     credPassword: n.rlnRelayCredPassword,
+    useMaxGasPrice: n.rlnRelayMaxGasPrice,
   )
 
 proc toNetworkConf(
diff --git a/tools/rln_keystore_generator/rln_keystore_generator.nim b/tools/rln_keystore_generator/rln_keystore_generator.nim
index 85df379827..aac9288e35 100644
--- a/tools/rln_keystore_generator/rln_keystore_generator.nim
+++ b/tools/rln_keystore_generator/rln_keystore_generator.nim
@@ -25,6 +25,7 @@ type RlnKeystoreGeneratorConf* = object
   credPassword*: string
   userMessageLimit*: uint64
   ethPrivateKey*: string
+  useMaxGasPrice*: bool
 
 proc doRlnKeystoreGenerator*(conf: RlnKeystoreGeneratorConf) =
   # 1. load configuration
@@ -59,6 +60,7 @@ proc doRlnKeystoreGenerator*(conf: RlnKeystoreGeneratorConf) =
     keystorePath: none(string),
     keystorePassword: none(string),
     ethPrivateKey: some(conf.ethPrivateKey),
+    useMaxGasPrice: conf.useMaxGasPrice,
     onFatalErrorAction: onFatalErrorAction,
   )
   try:
diff --git a/waku/waku_rln_relay/group_manager/on_chain/group_manager.nim b/waku/waku_rln_relay/group_manager/on_chain/group_manager.nim
index db68b2289f..5c136a2144 100644
--- a/waku/waku_rln_relay/group_manager/on_chain/group_manager.nim
+++ b/waku/waku_rln_relay/group_manager/on_chain/group_manager.nim
@@ -43,6 +43,7 @@ type
     registrationHandler*: Option[RegistrationHandler]
     latestProcessedBlock*: BlockNumber
     merkleProofCache*: seq[byte]
+    useMaxGasPrice*: bool
 
 # The below code is not working with the latest web3 version due to chainId being null (specifically on linea-sepolia)
 # TODO: find better solution than this custom sendEthCallWithoutParams call
@@ -227,9 +228,24 @@ method register*(
   let ethRpc = g.ethRpc.get()
   let wakuRlnContract = g.wakuRlnContract.get()
 
+  # Large gas price: 1000 Gwei (1e12 wei) for testing and extreme conditions
+  const MAX_PRACTICAL_GAS_PRICE = 1_000_000_000_000
+
   var gasPrice: int
-  g.retryWrapper(gasPrice, "Failed to get gas price"):
-    int(await ethRpc.provider.eth_gasPrice()) * 2
+  if g.useMaxGasPrice:
+    gasPrice = MAX_PRACTICAL_GAS_PRICE
+    debug "using maximum practical gas price", gasPrice = gasPrice
+  else:
+    g.retryWrapper(gasPrice, "Failed to get gas price"):
+      let currentGasPrice = int(await ethRpc.provider.eth_gasPrice())
+      # Check for potential overflow when multiplying by 2
+      if currentGasPrice > int.high div 2:
+        warn "gas price would overflow when doubled, using maximum practical gas price",
+          currentGasPrice = currentGasPrice
+        MAX_PRACTICAL_GAS_PRICE
+      else:
+        currentGasPrice * 2
+    debug "using dynamic gas price (2x current)", gasPrice = gasPrice
   let idCommitmentHex = identityCredential.idCommitment.inHex()
   info "identityCredential idCommitmentHex", idCommitment = idCommitmentHex
   let idCommitment = identityCredential.idCommitment.toUInt256()