Litecoin miners are being urged to leave the Coinotron mining pool due to an increase in its hash rate, which has been edging toward 51% of the network's total.

Despite warnings from the litecoin community across forums like reddit, the pool briefly crossed the 50% mark this week – leaving the litecoin network vulnerable to a so-called ‘51% attack’.

A 51% attack allows an attacker to make double-spend transactions, reverse transactions, prevent confirmations and corrupt the network.

The total hash rate of the litecoin network stands at 212.947 GH/s and Coinotron’s hash rate peaked at 115 GH/s. The litecoinpool chart below pegs the pool's current hashrate at 102 GH/s.

Although Coinotron has urged users to leave, its response has not gone down well with the community. Users have been criticising the pool over its failure to address the issue on the Coinotron bitcointalk thread.

Coinotron insists it is working to resolve the problem, but some community members feel it is simply not doing enough, with miners also shouldering part of the blame.

Although the situation has improved over the last few hours – Coinotron claims its hash rate has gone down from 115 GH/s to 93 GH/s – it is still litecoin's biggest mining pool by far.

An increasing number of specialist scrypt ASICs have gone online in recent weeks, and their appearance has amplified the problem of centralisation on the network.

Most of these ASICs are operated by relatively large miners, the top five account for about 50 GH/s. This means the network is anything but decentralized, yet many of these big miners are not solo mining – they are in the Coinotron pool.

More ASIC miners are on the way, so it is also possible that a sudden influx of new ASICs distributed between alternative pools will help level the playing field.

Back in January the bitcoin network faced a similar threat, when the Ghash.io mining pool started approaching the 51% mark. The pool took action to reduce its hash rate and issued a number of statements over the matter.

The temporary crisis led many in the community to develop a somewhat different approach which would essentially be a peer-to-peer mining pool with cross-platform support. Developers are still tackling the challenge, but so far such solutions have not been implemented on a large scale.