* Deputy prime minister says recordings were faked
* Lira dips to three-week low but recovers
* Erdogan scheduled to speak at election rallies (Adds deputy prime minister's comments, background)
By Humeyra Pamuk
ANKARA, Feb 27 (Reuters) - An audio recording purporting to be of Turkish Prime Minister Tayyip Erdogan giving his son business advice has been published on YouTube, following one earlier in the week that fuelled a corruption scandal and unnerved markets.
Erdogan said a similar post on the video-sharing site YouTube on Monday, allegedly of him telling his son Bilal to dispose of large sums of cash as a graft investigation erupted, had been faked by his political enemies.
The recordings, posted under pseudonyms, appeared within days of his AK Party launching its campaign for local elections in March, and are potentially the most damaging allegations in a scandal that became public on Dec. 17 with the arrest of businessmen close to Erdogan and three ministers' sons.
The audio track posted on Wednesday by the user "Haramzadeler" purported to be of Erdogan advising Bilal to hold out for a better offer in an unspecified business deal.
"Don't take it. Whatever he has promised us, he should bring this. If he is not going to bring that, there is no need," says the voice on the recording.
"The others are bringing. Why can't he bring? What do they think this business is? ... But don't worry, they will fall into our lap."
Reuters could not verify the authenticity of either recording and the deputy prime minister told reporters on Thursday that they were fabricated.
"On yesterday's developments, almost everyone agrees that they are a montage," Emrullah Isler said at a ceremony in Sudan, describing those responsible as an "illegitimate gang".
"A sort of political engineering is planned in Turkey through blackmail and tapes," he said. "Now we understand that they have wiretapped everyone and they want to scheme with threats, blackmail."
Erdogan accuses his former ally Fethullah Gulen, an Islamic cleric who now lives in the United States, of plotting to unseat him through a network of proteges in the judiciary and police. Gulen denies the accusations.
The lira weakened to a three-week low of 2.2525 to the dollar overnight from around 2.23 in Wednesday afternoon trade, with fragile sentiment due to the graft row compounded by emerging market worries over escalating tension in Ukraine, but had bounced back to 2.2335 by 1150 GMT. Shares in Istanbul were down 0.4 percent.
Erdogan's office released a statement on Monday describing the first recordings as "completely untrue and the product of an immoral montage".
Erdogan was scheduled to speak at election rallies in the western provinces of Burdur and Usak later on Thursday.
No company names are mentioned in Wednesday's audio recording but the voice purportedly of Bilal Erdogan refers to a "Mr. Sitki", saying he could not carry out a transaction.
An accompanying text within the YouTube clip says the reference is to Sitki Ayan, the chairman of Istanbul-based company Turang Transit Tasimacilik. The basis for that conclusion was not clear.
It could not immediately be determined what ties, if any, Turang or its chairman have to the Erdogan family.
Representatives of Turang were not immediately available to comment on Thursday morning.
Turang received a licence in 2010 to build part of a pipeline intended to carry Iranian and Turkmen gas to Europe through Turkey, according to its website.
It was granted incentives including tax exemptions on investments of up to 11.5 billion lira ($5.2 billion) from the government in December, according to the Economy Ministry's website.
($1 = 2.2279 Turkish lira) (Additional reporting by Asli Kandemir and Orhan Coskun; Writing by Nick Tattersall and Daren Butler; Editing by Jon Boyle and Kevin Liffey)
Our Standards: The Thomson Reuters Trust Principles.